638621252 has 12 divisors (see below), whose sum is σ = 1183327740. Its totient is φ = 300527616.

The previous prime is 638621237. The next prime is 638621257. The reversal of 638621252 is 252126836.

It can be written as a sum of positive squares in 2 ways, for example, as 583029316 + 55591936 = 24146^2 + 7456^2 .

It is not an unprimeable number, because it can be changed into a prime (638621257) 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, 4695677 + ... + 4695812.

It is an arithmetic number, because the mean of its divisors is an integer number (98610645).

Almost surely, 2^638621252 is an apocalyptic number.

It is an amenable number.

638621252 is a deficient number, since it is larger than the sum of its proper divisors (544706488).

638621252 is a wasteful number, since it uses less digits than its factorization.

638621252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9391510 (or 9391508 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 638621252 is about 25270.9566894489. The cubic root of 638621252 is about 861.1545930688.

The spelling of 638621252 in words is "six hundred thirty-eight million, six hundred twenty-one thousand, two hundred fifty-two".