87121521 has 16 divisors (see below), whose sum is σ = 129539520. Its totient is φ = 57869280.

The previous prime is 87121513. The next prime is 87121523. The reversal of 87121521 is 12512178.

It is not a de Polignac number, because 87121521 - 2³ = 87121513 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (87121523) 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, 1846 + ... + 13328.

It is an arithmetic number, because the mean of its divisors is an integer number (8096220).

Almost surely, 2^87121521 is an apocalyptic number.

It is an amenable number.

87121521 is a deficient number, since it is larger than the sum of its proper divisors (42417999).

87121521 is a wasteful number, since it uses less digits than its factorization.

87121521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11773 (or 11767 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 87121521 is about 9333.8909892927. The cubic root of 87121521 is about 443.3109747457.

Adding to 87121521 its reverse (12512178), we get a palindrome (99633699).

The spelling of 87121521 in words is "eighty-seven million, one hundred twenty-one thousand, five hundred twenty-one".