79917640 has 128 divisors (see below), whose sum is σ = 209952000. Its totient is φ = 27089920.

The previous prime is 79917637. The next prime is 79917641. The reversal of 79917640 is 4671997.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (79917641) 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 31 ways as a sum of consecutive naturals, for example, 536286 + ... + 536434.

It is an arithmetic number, because the mean of its divisors is an integer number (1640250).

Almost surely, 2^79917640 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 79917640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104976000).

79917640 is an abundant number, since it is smaller than the sum of its proper divisors (130034360).

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

79917640 is a wasteful number, since it uses less digits than its factorization.

79917640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247 (or 243 counting only the distinct ones).

The product of its (nonzero) digits is 95256, while the sum is 43.

The square root of 79917640 is about 8939.6666604522. Note that the first 5 decimals coincide. The cubic root of 79917640 is about 430.7390212004.

It can be divided in two parts, 79 and 917640, that added together give a palindrome (917719).

The spelling of 79917640 in words is "seventy-nine million, nine hundred seventeen thousand, six hundred forty".