87666521 has 2 divisors, whose sum is σ = 87666522. Its totient is φ = 87666520.

The previous prime is 87666511. The next prime is 87666587. The reversal of 87666521 is 12566678.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80802121 + 6864400 = 8989^2 + 2620^2 .

It is a cyclic number.

It is not a de Polignac number, because 87666521 - 2⁶ = 87666457 is a prime.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (87666511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43833260 + 43833261.

It is an arithmetic number, because the mean of its divisors is an integer number (43833261).

Almost surely, 2^87666521 is an apocalyptic number.

It is an amenable number.

87666521 is a deficient number, since it is larger than the sum of its proper divisors (1).

87666521 is an equidigital number, since it uses as much as digits as its factorization.

87666521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 41.

The square root of 87666521 is about 9363.0401579829. The cubic root of 87666521 is about 444.2334503330.

The spelling of 87666521 in words is "eighty-seven million, six hundred sixty-six thousand, five hundred twenty-one".