642942720 has 648 divisors, whose sum is σ = 2780812944. Its totient is φ = 136249344.

The previous prime is 642942719. The next prime is 642942721. The reversal of 642942720 is 27249246.

642942720 is a `hidden beast` number, since 642 + 9 + 4 + 2 + 7 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (642942719) and next prime (642942721).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642942721) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9596127 + ... + 9596193.

It is an arithmetic number, because the mean of its divisors is an integer number (4291378).

Almost surely, 2^642942720 is an apocalyptic number.

642942720 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 642942720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1390406472).

642942720 is an abundant number, since it is smaller than the sum of its proper divisors (2137870224).

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

642942720 is a wasteful number, since it uses less digits than its factorization.

642942720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 642942720 is about 25356.3151897116. The cubic root of 642942720 is about 863.0926688974.

The spelling of 642942720 in words is "six hundred forty-two million, nine hundred forty-two thousand, seven hundred twenty".