87821764 has 6 divisors (see below), whose sum is σ = 153688094. Its totient is φ = 43910880.

The previous prime is 87821759. The next prime is 87821771. The reversal of 87821764 is 46712878.

It can be written as a sum of positive squares in only one way, i.e., 66292164 + 21529600 = 8142^2 + 4640^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 87821764.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10977717 + ... + 10977724.

Almost surely, 2^87821764 is an apocalyptic number.

It is an amenable number.

87821764 is a deficient number, since it is larger than the sum of its proper divisors (65866330).

87821764 is a wasteful number, since it uses less digits than its factorization.

87821764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21955445 (or 21955443 counting only the distinct ones).

The product of its digits is 150528, while the sum is 43.

The square root of 87821764 is about 9371.3266936971. The cubic root of 87821764 is about 444.4955171771.

The spelling of 87821764 in words is "eighty-seven million, eight hundred twenty-one thousand, seven hundred sixty-four".