81935977 has 2 divisors, whose sum is σ = 81935978. Its totient is φ = 81935976.

The previous prime is 81935963. The next prime is 81935983. The reversal of 81935977 is 77953918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81920601 + 15376 = 9051^2 + 124^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81935977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81935977.

It is not a weakly prime, because it can be changed into another prime (81935927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40967988 + 40967989.

It is an arithmetic number, because the mean of its divisors is an integer number (40967989).

Almost surely, 2^81935977 is an apocalyptic number.

It is an amenable number.

81935977 is a deficient number, since it is larger than the sum of its proper divisors (1).

81935977 is an equidigital number, since it uses as much as digits as its factorization.

81935977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 49.

The square root of 81935977 is about 9051.8493690516. The cubic root of 81935977 is about 434.3350513578.

The spelling of 81935977 in words is "eighty-one million, nine hundred thirty-five thousand, nine hundred seventy-seven".