81164497 has 2 divisors, whose sum is σ = 81164498. Its totient is φ = 81164496.

The previous prime is 81164491. The next prime is 81164549. The reversal of 81164497 is 79446118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58354321 + 22810176 = 7639^2 + 4776^2 .

It is a cyclic number.

It is not a de Polignac number, because 81164497 - 2¹¹ = 81162449 is a prime.

It is not a weakly prime, because it can be changed into another prime (81164491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40582248 + 40582249.

It is an arithmetic number, because the mean of its divisors is an integer number (40582249).

Almost surely, 2^81164497 is an apocalyptic number.

It is an amenable number.

81164497 is a deficient number, since it is larger than the sum of its proper divisors (1).

81164497 is an equidigital number, since it uses as much as digits as its factorization.

81164497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 81164497 is about 9009.1340871362. The cubic root of 81164497 is about 432.9675690019.

The spelling of 81164497 in words is "eighty-one million, one hundred sixty-four thousand, four hundred ninety-seven".