521431216905 has 16 divisors (see below), whose sum is σ = 834699162240. Its totient is φ = 277960243968.

The previous prime is 521431216871. The next prime is 521431216909. The reversal of 521431216905 is 509612134125.

It is a happy number.

It is not a de Polignac number, because 521431216905 - 2¹⁸ = 521430954761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (521431216909) 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, 8493712 + ... + 8554881.

It is an arithmetic number, because the mean of its divisors is an integer number (52168697640).

Almost surely, 2^521431216905 is an apocalyptic number.

It is an amenable number.

521431216905 is a deficient number, since it is larger than the sum of its proper divisors (313267945335).

521431216905 is a wasteful number, since it uses less digits than its factorization.

521431216905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17050640.

The product of its (nonzero) digits is 64800, while the sum is 39.

The spelling of 521431216905 in words is "five hundred twenty-one billion, four hundred thirty-one million, two hundred sixteen thousand, nine hundred five".