72155691 has 16 divisors (see below), whose sum is σ = 108220320. Its totient is φ = 48102336.

The previous prime is 72155687. The next prime is 72155719. The reversal of 72155691 is 19655127.

It is not a de Polignac number, because 72155691 - 2² = 72155687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72155621) 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, 14310 + ... + 18683.

It is an arithmetic number, because the mean of its divisors is an integer number (6763770).

Almost surely, 2^72155691 is an apocalyptic number.

72155691 is a deficient number, since it is larger than the sum of its proper divisors (36064629).

72155691 is an frugal number, since it uses more digits than its factorization.

72155691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33014 (or 32996 counting only the distinct ones).

The product of its digits is 18900, while the sum is 36.

The square root of 72155691 is about 8494.4506002448. The cubic root of 72155691 is about 416.3164101492.

The spelling of 72155691 in words is "seventy-two million, one hundred fifty-five thousand, six hundred ninety-one".