638402255 has 16 divisors (see below), whose sum is σ = 789839424. Its totient is φ = 494991360.

The previous prime is 638402249. The next prime is 638402263. The reversal of 638402255 is 552204836.

It is a de Polignac number, because none of the positive numbers 2^k-638402255 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42095 + ... + 55215.

It is an arithmetic number, because the mean of its divisors is an integer number (49364964).

Almost surely, 2^638402255 is an apocalyptic number.

638402255 is a deficient number, since it is larger than the sum of its proper divisors (151437169).

638402255 is a wasteful number, since it uses less digits than its factorization.

638402255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13426.

The product of its (nonzero) digits is 57600, while the sum is 35.

The square root of 638402255 is about 25266.6233398925. The cubic root of 638402255 is about 861.0561456541.

The spelling of 638402255 in words is "six hundred thirty-eight million, four hundred two thousand, two hundred fifty-five".