521687481 has 64 divisors (see below), whose sum is σ = 843448320. Its totient is φ = 280687680.

The previous prime is 521687479. The next prime is 521687489. The reversal of 521687481 is 184786125.

It is not a de Polignac number, because 521687481 - 2¹ = 521687479 is a prime.

It is a super-2 number, since 2×521687481² = 544315655664250722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (521687489) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5064876 + ... + 5064978.

It is an arithmetic number, because the mean of its divisors is an integer number (13178880).

Almost surely, 2^521687481 is an apocalyptic number.

It is an amenable number.

521687481 is a deficient number, since it is larger than the sum of its proper divisors (321760839).

521687481 is a wasteful number, since it uses less digits than its factorization.

521687481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306.

The product of its digits is 107520, while the sum is 42.

The square root of 521687481 is about 22840.4790011068. The cubic root of 521687481 is about 805.0140712276.

The spelling of 521687481 in words is "five hundred twenty-one million, six hundred eighty-seven thousand, four hundred eighty-one".