642455940 has 96 divisors (see below), whose sum is σ = 2059223040. Its totient is φ = 146606976.

The previous prime is 642455923. The next prime is 642455951. The reversal of 642455940 is 49554246.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 445741 + ... + 447179.

It is an arithmetic number, because the mean of its divisors is an integer number (21450240).

Almost surely, 2^642455940 is an apocalyptic number.

642455940 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 642455940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1029611520).

642455940 is an abundant number, since it is smaller than the sum of its proper divisors (1416767100).

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

642455940 is a wasteful number, since it uses less digits than its factorization.

642455940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2521 (or 2519 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The square root of 642455940 is about 25346.7145800003. The cubic root of 642455940 is about 862.8747944735.

The spelling of 642455940 in words is "six hundred forty-two million, four hundred fifty-five thousand, nine hundred forty".