642976920 has 256 divisors, whose sum is σ = 2239488000. Its totient is φ = 163957248.

The previous prime is 642976909. The next prime is 642976949. The reversal of 642976920 is 29679246.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2690161 + ... + 2690399.

It is an arithmetic number, because the mean of its divisors is an integer number (8748000).

Almost surely, 2^642976920 is an apocalyptic number.

642976920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642976920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1119744000).

642976920 is an abundant number, since it is smaller than the sum of its proper divisors (1596511080).

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

642976920 is a wasteful number, since it uses less digits than its factorization.

642976920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359 (or 349 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The square root of 642976920 is about 25356.9895689532. The cubic root of 642976920 is about 863.1079720988.

It can be divided in two parts, 64297 and 6920, that added together give a palindrome (71217).

The spelling of 642976920 in words is "six hundred forty-two million, nine hundred seventy-six thousand, nine hundred twenty".