79721987 has 8 divisors (see below), whose sum is σ = 82713600. Its totient is φ = 76756680.

The previous prime is 79721977. The next prime is 79722023. The reversal of 79721987 is 78912797.

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

It is a cyclic number.

It is not a de Polignac number, because 79721987 - 2⁶ = 79721923 is a prime.

It is a super-2 number, since 2×79721987² = 12711190422456338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79721927) 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, 293 + ... + 12630.

It is an arithmetic number, because the mean of its divisors is an integer number (10339200).

Almost surely, 2^79721987 is an apocalyptic number.

79721987 is a deficient number, since it is larger than the sum of its proper divisors (2991613).

79721987 is a wasteful number, since it uses less digits than its factorization.

79721987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13153.

The product of its digits is 444528, while the sum is 50.

The square root of 79721987 is about 8928.7169850993. The cubic root of 79721987 is about 430.3872246540.

It can be divided in two parts, 79721 and 987, that added together give a palindrome (80708).

The spelling of 79721987 in words is "seventy-nine million, seven hundred twenty-one thousand, nine hundred eighty-seven".