81250979 has 2 divisors, whose sum is σ = 81250980. Its totient is φ = 81250978.

The previous prime is 81250943. The next prime is 81250991. The reversal of 81250979 is 97905218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81250979 - 2⁸ = 81250723 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81250919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40625489 + 40625490.

It is an arithmetic number, because the mean of its divisors is an integer number (40625490).

Almost surely, 2^81250979 is an apocalyptic number.

81250979 is a deficient number, since it is larger than the sum of its proper divisors (1).

81250979 is an equidigital number, since it uses as much as digits as its factorization.

81250979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 81250979 is about 9013.9324936456. The cubic root of 81250979 is about 433.1212922493.

The spelling of 81250979 in words is "eighty-one million, two hundred fifty thousand, nine hundred seventy-nine".