20172140 has 12 divisors (see below), whose sum is σ = 42361536. Its totient is φ = 8068848.

The previous prime is 20172137. The next prime is 20172157. The reversal of 20172140 is 4127102.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504284 + ... + 504323.

It is an arithmetic number, because the mean of its divisors is an integer number (3530128).

Almost surely, 2^20172140 is an apocalyptic number.

20172140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20172140 is an abundant number, since it is smaller than the sum of its proper divisors (22189396).

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

20172140 is a wasteful number, since it uses less digits than its factorization.

20172140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008616 (or 1008614 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 20172140 is about 4491.3405571165. The cubic root of 20172140 is about 272.2183044155.

Adding to 20172140 its reverse (4127102), we get a palindrome (24299242).

The spelling of 20172140 in words is "twenty million, one hundred seventy-two thousand, one hundred forty".