72171855 has 72 divisors (see below), whose sum is σ = 147891744. Its totient is φ = 32457600.

The previous prime is 72171839. The next prime is 72171859. The reversal of 72171855 is 55817127.

It is not a de Polignac number, because 72171855 - 2⁴ = 72171839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72171859) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 156325 + ... + 156785.

It is an arithmetic number, because the mean of its divisors is an integer number (2054052).

Almost surely, 2^72171855 is an apocalyptic number.

72171855 is an abundant number, since it is smaller than the sum of its proper divisors (75719889).

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

72171855 is a wasteful number, since it uses less digits than its factorization.

72171855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557 (or 547 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The square root of 72171855 is about 8495.4019916658. The cubic root of 72171855 is about 416.3474949508.

The spelling of 72171855 in words is "seventy-two million, one hundred seventy-one thousand, eight hundred fifty-five".