72121756 has 12 divisors (see below), whose sum is σ = 144243568. Its totient is φ = 30909312.

The previous prime is 72121697. The next prime is 72121757. The reversal of 72121756 is 65712127.

72121756 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72121757) 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, 1287861 + ... + 1287916.

Almost surely, 2^72121756 is an apocalyptic number.

It is an amenable number.

72121756 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

72121756 is a wasteful number, since it uses less digits than its factorization.

72121756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2575788 (or 2575786 counting only the distinct ones).

The product of its digits is 5880, while the sum is 31.

The square root of 72121756 is about 8492.4528847677. The cubic root of 72121756 is about 416.2511350358.

The spelling of 72121756 in words is "seventy-two million, one hundred twenty-one thousand, seven hundred fifty-six".