81500297 has 2 divisors, whose sum is σ = 81500298. Its totient is φ = 81500296.

The previous prime is 81500219. The next prime is 81500317. The reversal of 81500297 is 79200518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61528336 + 19971961 = 7844^2 + 4469^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81500297 is a prime.

It is a super-2 number, since 2×81500297² = 13284596822176418, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81500597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40750148 + 40750149.

It is an arithmetic number, because the mean of its divisors is an integer number (40750149).

Almost surely, 2^81500297 is an apocalyptic number.

It is an amenable number.

81500297 is a deficient number, since it is larger than the sum of its proper divisors (1).

81500297 is an equidigital number, since it uses as much as digits as its factorization.

81500297 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 81500297 is about 9027.7514919275. The cubic root of 81500297 is about 433.5638496734.

The spelling of 81500297 in words is "eighty-one million, five hundred thousand, two hundred ninety-seven".