638394790 has 24 divisors (see below), whose sum is σ = 1263074400. Its totient is φ = 232143120.

The previous prime is 638394787. The next prime is 638394791. The reversal of 638394790 is 97493836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638394791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 262590 + ... + 265009.

It is an arithmetic number, because the mean of its divisors is an integer number (52628100).

Almost surely, 2^638394790 is an apocalyptic number.

638394790 is a deficient number, since it is larger than the sum of its proper divisors (624679610).

638394790 is a wasteful number, since it uses less digits than its factorization.

638394790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527628 (or 527617 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 49.

The square root of 638394790 is about 25266.4756149329. The cubic root of 638394790 is about 861.0527894582.

The spelling of 638394790 in words is "six hundred thirty-eight million, three hundred ninety-four thousand, seven hundred ninety".