81575497 has 2 divisors, whose sum is σ = 81575498. Its totient is φ = 81575496.

The previous prime is 81575449. The next prime is 81575509. The reversal of 81575497 is 79457518.

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., 68873401 + 12702096 = 8299^2 + 3564^2 .

It is a cyclic number.

It is not a de Polignac number, because 81575497 - 2⁷ = 81575369 is a prime.

It is not a weakly prime, because it can be changed into another prime (81575437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40787748 + 40787749.

It is an arithmetic number, because the mean of its divisors is an integer number (40787749).

Almost surely, 2^81575497 is an apocalyptic number.

It is an amenable number.

81575497 is a deficient number, since it is larger than the sum of its proper divisors (1).

81575497 is an equidigital number, since it uses as much as digits as its factorization.

81575497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 352800, while the sum is 46.

The square root of 81575497 is about 9031.9154668320. The cubic root of 81575497 is about 433.6971578943.

The spelling of 81575497 in words is "eighty-one million, five hundred seventy-five thousand, four hundred ninety-seven".