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20646661 = 72949523
BaseRepresentation
bin100111011000…
…0101100000101
31102211221220011
41032300230011
520241143121
62014310221
7340331230
oct116605405
942757804
1020646661
1110722162
126ab8371
13437b879
142a56417
151c2c7e1
hex13b0b05

20646661 has 4 divisors (see below), whose sum is σ = 23596192. Its totient is φ = 17697132.

The previous prime is 20646631. The next prime is 20646667. The reversal of 20646661 is 16664602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20646661 - 213 = 20638469 is a prime.

It is a super-2 number, since 2×206466612 = 852569220897842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20646667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1474755 + ... + 1474768.

It is an arithmetic number, because the mean of its divisors is an integer number (5899048).

Almost surely, 220646661 is an apocalyptic number.

It is an amenable number.

20646661 is a deficient number, since it is larger than the sum of its proper divisors (2949531).

20646661 is an equidigital number, since it uses as much as digits as its factorization.

20646661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2949530.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 20646661 is about 4543.8597029398. The cubic root of 20646661 is about 274.3362991995.

The spelling of 20646661 in words is "twenty million, six hundred forty-six thousand, six hundred sixty-one".

Divisors: 1 7 2949523 20646661