638002690 has 32 divisors (see below), whose sum is σ = 1309497840. Its totient is φ = 221712384.

The previous prime is 638002667. The next prime is 638002733. The reversal of 638002690 is 96200836.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 282340809 + 355661881 = 16803^2 + 18859^2 .

It is a super-2 number, since 2×638002690² = 814094864894472200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

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, 142135 + ... + 146554.

Almost surely, 2^638002690 is an apocalyptic number.

638002690 is an abundant number, since it is smaller than the sum of its proper divisors (671495150).

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

638002690 is a wasteful number, since it uses less digits than its factorization.

638002690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288726.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 638002690 is about 25258.7151296340. The cubic root of 638002690 is about 860.8764680820.

The spelling of 638002690 in words is "six hundred thirty-eight million, two thousand, six hundred ninety".