87478021 has 2 divisors, whose sum is σ = 87478022. Its totient is φ = 87478020.

The previous prime is 87478009. The next prime is 87478057. The reversal of 87478021 is 12087478.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87329025 + 148996 = 9345^2 + 386^2 .

It is a cyclic number.

It is not a de Polignac number, because 87478021 - 2²⁵ = 53923589 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87478921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43739010 + 43739011.

It is an arithmetic number, because the mean of its divisors is an integer number (43739011).

Almost surely, 2^87478021 is an apocalyptic number.

It is an amenable number.

87478021 is a deficient number, since it is larger than the sum of its proper divisors (1).

87478021 is an equidigital number, since it uses as much as digits as its factorization.

87478021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 87478021 is about 9352.9685661826. The cubic root of 87478021 is about 443.9148258689.

The spelling of 87478021 in words is "eighty-seven million, four hundred seventy-eight thousand, twenty-one".