79998991 has 8 divisors (see below), whose sum is σ = 88388064. Its totient is φ = 72019200.

The previous prime is 79998973. The next prime is 79999009. The reversal of 79998991 is 19989997.

It is an interprime number because it is at equal distance from previous prime (79998973) and next prime (79999009).

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 79998991 - 2⁵ = 79998959 is a prime.

It is a super-3 number, since 3×79998991³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79998931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 101910 + ... + 102691.

It is an arithmetic number, because the mean of its divisors is an integer number (11048508).

Almost surely, 2^79998991 is an apocalyptic number.

79998991 is a deficient number, since it is larger than the sum of its proper divisors (8389073).

79998991 is a wasteful number, since it uses less digits than its factorization.

79998991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204641.

The product of its digits is 3306744, while the sum is 61.

The square root of 79998991 is about 8944.2155050066. The cubic root of 79998991 is about 430.8851264783.

The spelling of 79998991 in words is "seventy-nine million, nine hundred ninety-eight thousand, nine hundred ninety-one".