81499157 has 2 divisors, whose sum is σ = 81499158. Its totient is φ = 81499156.

The previous prime is 81499133. The next prime is 81499163. The reversal of 81499157 is 75199418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41036836 + 40462321 = 6406^2 + 6361^2 .

It is a cyclic number.

It is not a de Polignac number, because 81499157 - 2¹⁰ = 81498133 is a prime.

It is a super-2 number, since 2×81499157² = 13284225183421298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81499357) 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, 40749578 + 40749579.

It is an arithmetic number, because the mean of its divisors is an integer number (40749579).

Almost surely, 2^81499157 is an apocalyptic number.

It is an amenable number.

81499157 is a deficient number, since it is larger than the sum of its proper divisors (1).

81499157 is an equidigital number, since it uses as much as digits as its factorization.

81499157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 44.

The square root of 81499157 is about 9027.6883530614. The cubic root of 81499157 is about 433.5618281467.

The spelling of 81499157 in words is "eighty-one million, four hundred ninety-nine thousand, one hundred fifty-seven".