87213055521 has 16 divisors (see below), whose sum is σ = 116555351040. Its totient is φ = 58006470480.

The previous prime is 87213055493. The next prime is 87213055549. The reversal of 87213055521 is 12555031278.

It is an interprime number because it is at equal distance from previous prime (87213055493) and next prime (87213055549).

It is not a de Polignac number, because 87213055521 - 2²¹ = 87210958369 is a prime.

It is a super-2 number, since 2×87213055521² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 87213055521.

It is not an unprimeable number, because it can be changed into a prime (87213055021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6744300 + ... + 6757218.

It is an arithmetic number, because the mean of its divisors is an integer number (7284709440).

Almost surely, 2^87213055521 is an apocalyptic number.

It is an amenable number.

87213055521 is a deficient number, since it is larger than the sum of its proper divisors (29342295519).

87213055521 is a wasteful number, since it uses less digits than its factorization.

87213055521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17996.

The product of its (nonzero) digits is 84000, while the sum is 39.

Adding to 87213055521 its reverse (12555031278), we get a palindrome (99768086799).

The spelling of 87213055521 in words is "eighty-seven billion, two hundred thirteen million, fifty-five thousand, five hundred twenty-one".