72121788 has 72 divisors (see below), whose sum is σ = 188684496. Its totient is φ = 23212800.

The previous prime is 72121787. The next prime is 72121801. The reversal of 72121788 is 88712127.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72121787) 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, 193170 + ... + 193542.

It is an arithmetic number, because the mean of its divisors is an integer number (2620618).

Almost surely, 2^72121788 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72121788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94342248).

72121788 is an abundant number, since it is smaller than the sum of its proper divisors (116562708).

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

72121788 is a wasteful number, since it uses less digits than its factorization.

72121788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555 (or 550 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 72121788 is about 8492.4547687933. The cubic root of 72121788 is about 416.2511965986.

The spelling of 72121788 in words is "seventy-two million, one hundred twenty-one thousand, seven hundred eighty-eight".