638332490 has 16 divisors (see below), whose sum is σ = 1216586952. Its totient is φ = 240313344.

The previous prime is 638332481. The next prime is 638332511. The reversal of 638332490 is 94233836.

It can be written as a sum of positive squares in 4 ways, for example, as 638118121 + 214369 = 25261^2 + 463^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1877279 + ... + 1877618.

Almost surely, 2^638332490 is an apocalyptic number.

638332490 is a deficient number, since it is larger than the sum of its proper divisors (578254462).

638332490 is a wasteful number, since it uses less digits than its factorization.

638332490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3754921.

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 638332490 is about 25265.2427259269. The cubic root of 638332490 is about 861.0247789257.

The spelling of 638332490 in words is "six hundred thirty-eight million, three hundred thirty-two thousand, four hundred ninety".