138644253 has 24 divisors (see below), whose sum is σ = 227972160. Its totient is φ = 80372160.

The previous prime is 138644227. The next prime is 138644257. The reversal of 138644253 is 352446831.

138644253 is a `hidden beast` number, since 1 + 3 + 8 + 644 + 2 + 5 + 3 = 666.

It is not a de Polignac number, because 138644253 - 2⁵ = 138644221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138644257) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28168 + ... + 32721.

It is an arithmetic number, because the mean of its divisors is an integer number (9498840).

Almost surely, 2^138644253 is an apocalyptic number.

It is an amenable number.

138644253 is a deficient number, since it is larger than the sum of its proper divisors (89327907).

138644253 is a wasteful number, since it uses less digits than its factorization.

138644253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60929 (or 60926 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 138644253 is about 11774.7294236428. The cubic root of 138644253 is about 517.5678493970.

The spelling of 138644253 in words is "one hundred thirty-eight million, six hundred forty-four thousand, two hundred fifty-three".