87437921 has 4 divisors (see below), whose sum is σ = 88076292. Its totient is φ = 86799552.

The previous prime is 87437899. The next prime is 87437951. The reversal of 87437921 is 12973478.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39551521 + 47886400 = 6289^2 + 6920^2 .

It is a cyclic number.

It is not a de Polignac number, because 87437921 - 2¹⁰ = 87436897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87437951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 318980 + ... + 319253.

It is an arithmetic number, because the mean of its divisors is an integer number (22019073).

Almost surely, 2^87437921 is an apocalyptic number.

It is an amenable number.

87437921 is a deficient number, since it is larger than the sum of its proper divisors (638371).

87437921 is a wasteful number, since it uses less digits than its factorization.

87437921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638370.

The product of its digits is 84672, while the sum is 41.

The square root of 87437921 is about 9350.8246160432. The cubic root of 87437921 is about 443.8469851892.

The spelling of 87437921 in words is "eighty-seven million, four hundred thirty-seven thousand, nine hundred twenty-one".