81499499 has 2 divisors, whose sum is σ = 81499500. Its totient is φ = 81499498.

The previous prime is 81499487. The next prime is 81499529. The reversal of 81499499 is 99499418.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81499499 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81499499.

It is not a weakly prime, because it can be changed into another prime (81499399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40749749 + 40749750.

It is an arithmetic number, because the mean of its divisors is an integer number (40749750).

Almost surely, 2^81499499 is an apocalyptic number.

81499499 is a deficient number, since it is larger than the sum of its proper divisors (1).

81499499 is an equidigital number, since it uses as much as digits as its factorization.

81499499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 839808, while the sum is 53.

The square root of 81499499 is about 9027.7072947676. The cubic root of 81499499 is about 433.5624346067.

The spelling of 81499499 in words is "eighty-one million, four hundred ninety-nine thousand, four hundred ninety-nine".