81929752537 has 2 divisors, whose sum is σ = 81929752538. Its totient is φ = 81929752536.

The previous prime is 81929752477. The next prime is 81929752543. The reversal of 81929752537 is 73525792918.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75048054601 + 6881697936 = 273949^2 + 82956^2 .

It is a cyclic number.

It is not a de Polignac number, because 81929752537 - 2³⁵ = 47570014169 is a prime.

It is not a weakly prime, because it can be changed into another prime (81929752547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40964876268 + 40964876269.

It is an arithmetic number, because the mean of its divisors is an integer number (40964876269).

Almost surely, 2^81929752537 is an apocalyptic number.

It is an amenable number.

81929752537 is a deficient number, since it is larger than the sum of its proper divisors (1).

81929752537 is an equidigital number, since it uses as much as digits as its factorization.

81929752537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9525600, while the sum is 58.

The spelling of 81929752537 in words is "eighty-one billion, nine hundred twenty-nine million, seven hundred fifty-two thousand, five hundred thirty-seven".