81500597 has 2 divisors, whose sum is σ = 81500598. Its totient is φ = 81500596.

The previous prime is 81500563. The next prime is 81500623. The reversal of 81500597 is 79500518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77281681 + 4218916 = 8791^2 + 2054^2 .

It is a cyclic number.

It is not a de Polignac number, because 81500597 - 2²⁶ = 14391733 is a prime.

It is a super-2 number, since 2×81500597² = 13284694622712818, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81500297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40750298 + 40750299.

It is an arithmetic number, because the mean of its divisors is an integer number (40750299).

Almost surely, 2^81500597 is an apocalyptic number.

It is an amenable number.

81500597 is a deficient number, since it is larger than the sum of its proper divisors (1).

81500597 is an equidigital number, since it uses as much as digits as its factorization.

81500597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 35.

The square root of 81500597 is about 9027.7681073452. The cubic root of 81500597 is about 433.5643816510.

The spelling of 81500597 in words is "eighty-one million, five hundred thousand, five hundred ninety-seven".