81626999039 has 4 divisors (see below), whose sum is σ = 81921681624. Its totient is φ = 81332316456.

The previous prime is 81626998993. The next prime is 81626999089. The reversal of 81626999039 is 93099962618.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81626999039 is a prime.

It is a super-2 number, since 2×81626999039² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81626999089) 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, 147340877 + ... + 147341430.

It is an arithmetic number, because the mean of its divisors is an integer number (20480420406).

Almost surely, 2^81626999039 is an apocalyptic number.

81626999039 is a deficient number, since it is larger than the sum of its proper divisors (294682585).

81626999039 is a wasteful number, since it uses less digits than its factorization.

81626999039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294682584.

The product of its (nonzero) digits is 11337408, while the sum is 62.

The spelling of 81626999039 in words is "eighty-one billion, six hundred twenty-six million, nine hundred ninety-nine thousand, thirty-nine".