81499357 has 2 divisors, whose sum is σ = 81499358. Its totient is φ = 81499356.

The previous prime is 81499351. The next prime is 81499387. The reversal of 81499357 is 75399418.

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., 78605956 + 2893401 = 8866^2 + 1701^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81499357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81499351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40749678 + 40749679.

It is an arithmetic number, because the mean of its divisors is an integer number (40749679).

Almost surely, 2^81499357 is an apocalyptic number.

It is an amenable number.

81499357 is a deficient number, since it is larger than the sum of its proper divisors (1).

81499357 is an equidigital number, since it uses as much as digits as its factorization.

81499357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 46.

The square root of 81499357 is about 9027.6994300874. The cubic root of 81499357 is about 433.5621828019.

The spelling of 81499357 in words is "eighty-one million, four hundred ninety-nine thousand, three hundred fifty-seven".