87921979 has 2 divisors, whose sum is σ = 87921980. Its totient is φ = 87921978.

The previous prime is 87921959. The next prime is 87921991. The reversal of 87921979 is 97912978.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 87921979 - 2⁵ = 87921947 is a prime.

It is not a weakly prime, because it can be changed into another prime (87921929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43960989 + 43960990.

It is an arithmetic number, because the mean of its divisors is an integer number (43960990).

Almost surely, 2^87921979 is an apocalyptic number.

87921979 is a deficient number, since it is larger than the sum of its proper divisors (1).

87921979 is an equidigital number, since it uses as much as digits as its factorization.

87921979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 571536, while the sum is 52.

The square root of 87921979 is about 9376.6720642241. The cubic root of 87921979 is about 444.6645268592.

Subtracting 87921979 from its reverse (97912978), we obtain a palindrome (9990999).

The spelling of 87921979 in words is "eighty-seven million, nine hundred twenty-one thousand, nine hundred seventy-nine".