642855420 has 48 divisors (see below), whose sum is σ = 1999996320. Its totient is φ = 171427968.

The previous prime is 642855413. The next prime is 642855449. The reversal of 642855420 is 24558246.

It is a happy number.

642855420 is a `hidden beast` number, since 64 + 28 + 554 + 20 = 666.

642855420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 594697 + ... + 595776.

It is an arithmetic number, because the mean of its divisors is an integer number (41666590).

Almost surely, 2^642855420 is an apocalyptic number.

642855420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642855420 is an abundant number, since it is smaller than the sum of its proper divisors (1357140900).

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

642855420 is a wasteful number, since it uses less digits than its factorization.

642855420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1190491 (or 1190483 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 642855420 is about 25354.5936666317. The cubic root of 642855420 is about 863.0536030013.

The spelling of 642855420 in words is "six hundred forty-two million, eight hundred fifty-five thousand, four hundred twenty".