72111921 has 16 divisors (see below), whose sum is σ = 113430528. Its totient is φ = 39877200.

The previous prime is 72111917. The next prime is 72111937. The reversal of 72111921 is 12911127.

It is not a de Polignac number, because 72111921 - 2² = 72111917 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 72111891 and 72111900.

It is not an unprimeable number, because it can be changed into a prime (72111421) 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, 54735 + ... + 56036.

It is an arithmetic number, because the mean of its divisors is an integer number (7089408).

Almost surely, 2^72111921 is an apocalyptic number.

It is an amenable number.

72111921 is a deficient number, since it is larger than the sum of its proper divisors (41318607).

72111921 is a wasteful number, since it uses less digits than its factorization.

72111921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110812.

The product of its digits is 252, while the sum is 24.

The square root of 72111921 is about 8491.8738214837. The cubic root of 72111921 is about 416.2322132558.

The spelling of 72111921 in words is "seventy-two million, one hundred eleven thousand, nine hundred twenty-one".