87399921 has 16 divisors (see below), whose sum is σ = 133430144. Its totient is φ = 49849344.

The previous prime is 87399899. The next prime is 87399953. The reversal of 87399921 is 12999378.

It is not a de Polignac number, because 87399921 - 2⁵ = 87399889 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (87399971) 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, 8511 + ... + 15723.

It is an arithmetic number, because the mean of its divisors is an integer number (8339384).

Almost surely, 2^87399921 is an apocalyptic number.

It is an amenable number.

87399921 is a deficient number, since it is larger than the sum of its proper divisors (46030223).

87399921 is a wasteful number, since it uses less digits than its factorization.

87399921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7800.

The product of its digits is 244944, while the sum is 48.

The square root of 87399921 is about 9348.7924888726. The cubic root of 87399921 is about 443.7826781198.

The spelling of 87399921 in words is "eighty-seven million, three hundred ninety-nine thousand, nine hundred twenty-one".