646974553 has 8 divisors (see below), whose sum is σ = 655230600. Its totient is φ = 638740608.

The previous prime is 646974511. The next prime is 646974571. The reversal of 646974553 is 355479646.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 24571849 + 622402704 = 4957^2 + 24948^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 646974553 - 2¹³ = 646966361 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 646974497 and 646974506.

It is not an unprimeable number, because it can be changed into a prime (646914553) 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 7 ways as a sum of consecutive naturals, for example, 57975 + ... + 68227.

It is an arithmetic number, because the mean of its divisors is an integer number (81903825).

Almost surely, 2^646974553 is an apocalyptic number.

It is an amenable number.

646974553 is a deficient number, since it is larger than the sum of its proper divisors (8256047).

646974553 is a wasteful number, since it uses less digits than its factorization.

646974553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11051.

The product of its digits is 2721600, while the sum is 49.

The square root of 646974553 is about 25435.6944666349. The cubic root of 646974553 is about 864.8930349875.

The spelling of 646974553 in words is "six hundred forty-six million, nine hundred seventy-four thousand, five hundred fifty-three".