80639999 has 4 divisors (see below), whose sum is σ = 87970920. Its totient is φ = 73309080.

The previous prime is 80639969. The next prime is 80640011. The reversal of 80639999 is 99993608.

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 80639999 - 2²⁰ = 79591423 is a prime.

It is a Duffinian number.

80639999 is a modest number, since divided by 9999 gives 8063 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 80639999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80639929) 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, 3665444 + ... + 3665465.

It is an arithmetic number, because the mean of its divisors is an integer number (21992730).

Almost surely, 2^80639999 is an apocalyptic number.

80639999 is a deficient number, since it is larger than the sum of its proper divisors (7330921).

80639999 is a wasteful number, since it uses less digits than its factorization.

80639999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7330920.

The product of its (nonzero) digits is 944784, while the sum is 53.

The square root of 80639999 is about 8979.9776725780. The cubic root of 80639999 is about 432.0329175163.

The spelling of 80639999 in words is "eighty million, six hundred thirty-nine thousand, nine hundred ninety-nine".