81599995 has 4 divisors (see below), whose sum is σ = 97920000. Its totient is φ = 65279992.

The previous prime is 81599993. The next prime is 81600023. The reversal of 81599995 is 59999518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81599995 - 2¹ = 81599993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81599993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8159995 + ... + 8160004.

It is an arithmetic number, because the mean of its divisors is an integer number (24480000).

Almost surely, 2^81599995 is an apocalyptic number.

81599995 is a deficient number, since it is larger than the sum of its proper divisors (16320005).

81599995 is a wasteful number, since it uses less digits than its factorization.

81599995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16320004.

The product of its digits is 1312200, while the sum is 55.

The square root of 81599995 is about 9033.2715557543. The cubic root of 81599995 is about 433.7405681910.

The spelling of 81599995 in words is "eighty-one million, five hundred ninety-nine thousand, nine hundred ninety-five".