638655089 has 4 divisors (see below), whose sum is σ = 644514420. Its totient is φ = 632795760.

The previous prime is 638655067. The next prime is 638655161. The reversal of 638655089 is 980556836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 190909489 + 447745600 = 13817^2 + 21160^2 .

It is a cyclic number.

It is not a de Polignac number, because 638655089 - 2²⁰ = 637606513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638655029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2929502 + ... + 2929719.

It is an arithmetic number, because the mean of its divisors is an integer number (161128605).

Almost surely, 2^638655089 is an apocalyptic number.

It is an amenable number.

638655089 is a deficient number, since it is larger than the sum of its proper divisors (5859331).

638655089 is a wasteful number, since it uses less digits than its factorization.

638655089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5859330.

The product of its (nonzero) digits is 1555200, while the sum is 50.

The square root of 638655089 is about 25271.6261645348. The cubic root of 638655089 is about 861.1698020696.

The spelling of 638655089 in words is "six hundred thirty-eight million, six hundred fifty-five thousand, eighty-nine".