76891681 has 2 divisors, whose sum is σ = 76891682. Its totient is φ = 76891680.

The previous prime is 76891657. The next prime is 76891709. The reversal of 76891681 is 18619867.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66912400 + 9979281 = 8180^2 + 3159^2 .

It is a cyclic number.

It is not a de Polignac number, because 76891681 - 2⁵ = 76891649 is a prime.

It is a super-2 number, since 2×76891681² = 11824661214011522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (76891601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38445840 + 38445841.

It is an arithmetic number, because the mean of its divisors is an integer number (38445841).

Almost surely, 2^76891681 is an apocalyptic number.

It is an amenable number.

76891681 is a deficient number, since it is larger than the sum of its proper divisors (1).

76891681 is an equidigital number, since it uses as much as digits as its factorization.

76891681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 46.

The square root of 76891681 is about 8768.7901674062. The cubic root of 76891681 is about 425.2325020798.

The spelling of 76891681 in words is "seventy-six million, eight hundred ninety-one thousand, six hundred eighty-one".