521666431 has 16 divisors (see below), whose sum is σ = 615450528. Its totient is φ = 435916800.

The previous prime is 521666407. The next prime is 521666443. The reversal of 521666431 is 134666125.

It is not a de Polignac number, because 521666431 - 2⁵ = 521666399 is a prime.

It is a super-2 number, since 2×521666431² = 544271730464555522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521666491) 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, 26895 + ... + 42031.

It is an arithmetic number, because the mean of its divisors is an integer number (38465658).

Almost surely, 2^521666431 is an apocalyptic number.

521666431 is a deficient number, since it is larger than the sum of its proper divisors (93784097).

521666431 is a wasteful number, since it uses less digits than its factorization.

521666431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15402.

The product of its digits is 25920, while the sum is 34.

The square root of 521666431 is about 22840.0181917616. The cubic root of 521666431 is about 805.0032436889.

The spelling of 521666431 in words is "five hundred twenty-one million, six hundred sixty-six thousand, four hundred thirty-one".