80659991 has 4 divisors (see below), whose sum is σ = 83441400. Its totient is φ = 77878584.

The previous prime is 80659979. The next prime is 80659993. The reversal of 80659991 is 19995608.

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 80659991 - 2¹⁰ = 80658967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80659993) 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, 1390661 + ... + 1390718.

It is an arithmetic number, because the mean of its divisors is an integer number (20860350).

Almost surely, 2^80659991 is an apocalyptic number.

80659991 is a deficient number, since it is larger than the sum of its proper divisors (2781409).

80659991 is a wasteful number, since it uses less digits than its factorization.

80659991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2781408.

The product of its (nonzero) digits is 174960, while the sum is 47.

The square root of 80659991 is about 8981.0907466744. The cubic root of 80659991 is about 432.0686172869.

The spelling of 80659991 in words is "eighty million, six hundred fifty-nine thousand, nine hundred ninety-one".