642899808 has 96 divisors (see below), whose sum is σ = 1973865600. Its totient is φ = 203015808.

The previous prime is 642899797. The next prime is 642899819. The reversal of 642899808 is 808998246.

642899808 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (642899797) and next prime (642899819).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 3166 + ... + 35997.

It is an arithmetic number, because the mean of its divisors is an integer number (20561100).

Almost surely, 2^642899808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642899808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (986932800).

642899808 is an abundant number, since it is smaller than the sum of its proper divisors (1330965792).

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

642899808 is a wasteful number, since it uses less digits than its factorization.

642899808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39201 (or 39187 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The square root of 642899808 is about 25355.4689958597. The cubic root of 642899808 is about 863.0734666390.

The spelling of 642899808 in words is "six hundred forty-two million, eight hundred ninety-nine thousand, eight hundred eight".