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6643644653 = 35171889009
BaseRepresentation
bin1100010111111110…
…11111100011101101
3122011000012010011002
412023333133203231
5102101233112103
63015124210045
7323431022252
oct61377374355
918130163132
106643644653
1128aa189618
121354b39925
1381b5360a9
144704b7429
1528d3c7488
hex18bfdf8ed

6643644653 has 4 divisors (see below), whose sum is σ = 6645537180. Its totient is φ = 6641752128.

The previous prime is 6643644647. The next prime is 6643644661. The reversal of 6643644653 is 3564463466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3564463466 = 21782231733.

It can be written as a sum of positive squares in 2 ways, for example, as 3618864649 + 3024780004 = 60157^2 + 54998^2 .

It is a cyclic number.

It is not a de Polignac number, because 6643644653 - 212 = 6643640557 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6643644598 and 6643644607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6643644643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 940988 + ... + 948021.

It is an arithmetic number, because the mean of its divisors is an integer number (1661384295).

Almost surely, 26643644653 is an apocalyptic number.

It is an amenable number.

6643644653 is a deficient number, since it is larger than the sum of its proper divisors (1892527).

6643644653 is a wasteful number, since it uses less digits than its factorization.

6643644653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1892526.

The product of its digits is 3732480, while the sum is 47.

The square root of 6643644653 is about 81508.5557042940. Note that the first 3 decimals coincide. The cubic root of 6643644653 is about 1879.9031047277.

The spelling of 6643644653 in words is "six billion, six hundred forty-three million, six hundred forty-four thousand, six hundred fifty-three".

Divisors: 1 3517 1889009 6643644653