79821591 has 8 divisors (see below), whose sum is σ = 107526384. Its totient is φ = 52665600.

The previous prime is 79821587. The next prime is 79821593. The reversal of 79821591 is 19512897.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 79821591 - 2² = 79821587 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79821593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136860 + ... + 137441.

It is an arithmetic number, because the mean of its divisors is an integer number (13440798).

Almost surely, 2^79821591 is an apocalyptic number.

79821591 is a deficient number, since it is larger than the sum of its proper divisors (27704793).

79821591 is a wasteful number, since it uses less digits than its factorization.

79821591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274401.

The product of its digits is 45360, while the sum is 42.

The square root of 79821591 is about 8934.2929770632. The cubic root of 79821591 is about 430.5663908205.

The spelling of 79821591 in words is "seventy-nine million, eight hundred twenty-one thousand, five hundred ninety-one".