81510712057 has 2 divisors, whose sum is σ = 81510712058. Its totient is φ = 81510712056.

The previous prime is 81510712051. The next prime is 81510712067. The reversal of 81510712057 is 75021701518.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69076454976 + 12434257081 = 262824^2 + 111509^2 .

It is a cyclic number.

It is not a de Polignac number, because 81510712057 - 2¹⁹ = 81510187769 is a prime.

It is not a weakly prime, because it can be changed into another prime (81510712051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40755356028 + 40755356029.

It is an arithmetic number, because the mean of its divisors is an integer number (40755356029).

Almost surely, 2^81510712057 is an apocalyptic number.

It is an amenable number.

81510712057 is a deficient number, since it is larger than the sum of its proper divisors (1).

81510712057 is an equidigital number, since it uses as much as digits as its factorization.

81510712057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19600, while the sum is 37.

The spelling of 81510712057 in words is "eighty-one billion, five hundred ten million, seven hundred twelve thousand, fifty-seven".