642455939 has 4 divisors (see below), whose sum is σ = 650196456. Its totient is φ = 634715424.

The previous prime is 642455923. The next prime is 642455951. The reversal of 642455939 is 939554246.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 642455939 - 2⁴ = 642455923 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642455893 and 642455902.

It is not an unprimeable number, because it can be changed into a prime (642455239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3870134 + ... + 3870299.

It is an arithmetic number, because the mean of its divisors is an integer number (162549114).

Almost surely, 2^642455939 is an apocalyptic number.

642455939 is a deficient number, since it is larger than the sum of its proper divisors (7740517).

642455939 is an equidigital number, since it uses as much as digits as its factorization.

642455939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7740516.

The product of its digits is 1166400, while the sum is 47.

The square root of 642455939 is about 25346.7145602739. The cubic root of 642455939 is about 862.8747940258.

The spelling of 642455939 in words is "six hundred forty-two million, four hundred fifty-five thousand, nine hundred thirty-nine".