642579798 has 64 divisors (see below), whose sum is σ = 1520483328. Its totient is φ = 177223680.

The previous prime is 642579779. The next prime is 642579823. The reversal of 642579798 is 897975246.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 165111 + ... + 168957.

It is an arithmetic number, because the mean of its divisors is an integer number (23757552).

Almost surely, 2^642579798 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642579798, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (760241664).

642579798 is an abundant number, since it is smaller than the sum of its proper divisors (877903530).

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

642579798 is a wasteful number, since it uses less digits than its factorization.

642579798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3997.

The product of its digits is 7620480, while the sum is 57.

The square root of 642579798 is about 25349.1577374871. The cubic root of 642579798 is about 862.9302416372.

The spelling of 642579798 in words is "six hundred forty-two million, five hundred seventy-nine thousand, seven hundred ninety-eight".