521391641 has 16 divisors (see below), whose sum is σ = 544346880. Its totient is φ = 499035600.

The previous prime is 521391631. The next prime is 521391653. The reversal of 521391641 is 146193125.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521391641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521391598 and 521391607.

It is not an unprimeable number, because it can be changed into a prime (521391631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 495566 + ... + 496616.

It is an arithmetic number, because the mean of its divisors is an integer number (34021680).

Almost surely, 2^521391641 is an apocalyptic number.

It is an amenable number.

521391641 is a deficient number, since it is larger than the sum of its proper divisors (22955239).

521391641 is a wasteful number, since it uses less digits than its factorization.

521391641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1316.

The product of its digits is 6480, while the sum is 32.

The square root of 521391641 is about 22834.0018612594. The cubic root of 521391641 is about 804.8618725751.

The spelling of 521391641 in words is "five hundred twenty-one million, three hundred ninety-one thousand, six hundred forty-one".