72121655 has 16 divisors (see below), whose sum is σ = 89766144. Its totient is φ = 55568640.

The previous prime is 72121639. The next prime is 72121691. The reversal of 72121655 is 55612127.

It is not a de Polignac number, because 72121655 - 2⁴ = 72121639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35117 + ... + 37113.

It is an arithmetic number, because the mean of its divisors is an integer number (5610384).

Almost surely, 2^72121655 is an apocalyptic number.

72121655 is a deficient number, since it is larger than the sum of its proper divisors (17644489).

72121655 is a wasteful number, since it uses less digits than its factorization.

72121655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2266.

The product of its digits is 4200, while the sum is 29.

The square root of 72121655 is about 8492.4469383094. The cubic root of 72121655 is about 416.2509407284.

The spelling of 72121655 in words is "seventy-two million, one hundred twenty-one thousand, six hundred fifty-five".