72100638 has 32 divisors (see below), whose sum is σ = 169650720. Its totient is φ = 22619520.

The previous prime is 72100631. The next prime is 72100681. The reversal of 72100638 is 83600127.

72100638 is a `hidden beast` number, since 7 + 21 + 0 + 0 + 638 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72100631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38353 + ... + 40188.

It is an arithmetic number, because the mean of its divisors is an integer number (5301585).

Almost surely, 2^72100638 is an apocalyptic number.

72100638 is an abundant number, since it is smaller than the sum of its proper divisors (97550082).

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

72100638 is a wasteful number, since it uses less digits than its factorization.

72100638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78569 (or 78563 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 72100638 is about 8491.2094544888. The cubic root of 72100638 is about 416.2105035165.

The spelling of 72100638 in words is "seventy-two million, one hundred thousand, six hundred thirty-eight".