20157172 has 72 divisors (see below), whose sum is σ = 44561664. Its totient is φ = 7807488.

The previous prime is 20157169. The next prime is 20157187. The reversal of 20157172 is 27175102.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 380298 + ... + 380350.

It is an arithmetic number, because the mean of its divisors is an integer number (618912).

Almost surely, 2^20157172 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20157172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22280832).

20157172 is an abundant number, since it is smaller than the sum of its proper divisors (24404492).

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

20157172 is a wasteful number, since it uses less digits than its factorization.

20157172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 20157172 is about 4489.6739302537. The cubic root of 20157172 is about 272.1509578707.

The spelling of 20157172 in words is "twenty million, one hundred fifty-seven thousand, one hundred seventy-two".