79981920 has 144 divisors (see below), whose sum is σ = 277346160. Its totient is φ = 20984832.

The previous prime is 79981907. The next prime is 79981927. The reversal of 79981920 is 2918997.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79981927) 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 23 ways as a sum of consecutive naturals, for example, 96066 + ... + 96894.

It is an arithmetic number, because the mean of its divisors is an integer number (1926015).

Almost surely, 2^79981920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 79981920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138673080).

79981920 is an abundant number, since it is smaller than the sum of its proper divisors (197364240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

79981920 is a wasteful number, since it uses less digits than its factorization.

79981920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917 (or 906 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 79981920 is about 8943.2611501622. The cubic root of 79981920 is about 430.8544754114.

The spelling of 79981920 in words is "seventy-nine million, nine hundred eighty-one thousand, nine hundred twenty".