72121123 has 16 divisors (see below), whose sum is σ = 80317440. Its totient is φ = 64411776.

The previous prime is 72121117. The next prime is 72121183. The reversal of 72121123 is 32112127.

It is a de Polignac number, because none of the positive numbers 2^k-72121123 is a prime.

It is a super-2 number, since 2×72121123² = 10402912765562258, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72121123.

It is not an unprimeable number, because it can be changed into a prime (72121183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53686 + ... + 55012.

It is an arithmetic number, because the mean of its divisors is an integer number (5019840).

Almost surely, 2^72121123 is an apocalyptic number.

72121123 is a deficient number, since it is larger than the sum of its proper divisors (8196317).

72121123 is a wasteful number, since it uses less digits than its factorization.

72121123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1506.

The product of its digits is 168, while the sum is 19.

The square root of 72121123 is about 8492.4156163014. The cubic root of 72121123 is about 416.2499172446.

The spelling of 72121123 in words is "seventy-two million, one hundred twenty-one thousand, one hundred twenty-three".