81964079 has 2 divisors, whose sum is σ = 81964080. Its totient is φ = 81964078.

The previous prime is 81964067. The next prime is 81964109. The reversal of 81964079 is 97046918.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81964079 is a prime.

It is a super-2 number, since 2×81964079² = 13436220492636482, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81964979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40982039 + 40982040.

It is an arithmetic number, because the mean of its divisors is an integer number (40982040).

Almost surely, 2^81964079 is an apocalyptic number.

81964079 is a deficient number, since it is larger than the sum of its proper divisors (1).

81964079 is an equidigital number, since it uses as much as digits as its factorization.

81964079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 81964079 is about 9053.4015154526. The cubic root of 81964079 is about 434.3847010514.

The spelling of 81964079 in words is "eighty-one million, nine hundred sixty-four thousand, seventy-nine".