642525408 has 72 divisors (see below), whose sum is σ = 2088214128. Its totient is φ = 183578112.

The previous prime is 642525397. The next prime is 642525409. The reversal of 642525408 is 804525246.

It is a happy number.

642525408 is a `hidden beast` number, since 64 + 2 + 52 + 540 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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 (642525409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 157341 + ... + 161372.

It is an arithmetic number, because the mean of its divisors is an integer number (29002974).

Almost surely, 2^642525408 is an apocalyptic number.

It is an amenable number.

642525408 is an abundant number, since it is smaller than the sum of its proper divisors (1445688720).

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

642525408 is a wasteful number, since it uses less digits than its factorization.

642525408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318736 (or 318725 counting only the distinct ones).

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

The square root of 642525408 is about 25348.0848980746. The cubic root of 642525408 is about 862.9058938959.

The spelling of 642525408 in words is "six hundred forty-two million, five hundred twenty-five thousand, four hundred eight".