81877987 has 2 divisors, whose sum is σ = 81877988. Its totient is φ = 81877986.

The previous prime is 81877979. The next prime is 81877993. The reversal of 81877987 is 78977818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81877987 - 2³ = 81877979 is a prime.

It is not a weakly prime, because it can be changed into another prime (81877927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40938993 + 40938994.

It is an arithmetic number, because the mean of its divisors is an integer number (40938994).

Almost surely, 2^81877987 is an apocalyptic number.

81877987 is a deficient number, since it is larger than the sum of its proper divisors (1).

81877987 is an equidigital number, since it uses as much as digits as its factorization.

81877987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1580544, while the sum is 55.

The square root of 81877987 is about 9048.6455892581. The cubic root of 81877987 is about 434.2325606289.

The spelling of 81877987 in words is "eighty-one million, eight hundred seventy-seven thousand, nine hundred eighty-seven".