20172144 has 20 divisors (see below), whose sum is σ = 52111496. Its totient is φ = 6724032.

The previous prime is 20172137. The next prime is 20172157. The reversal of 20172144 is 44127102.

It is a happy number.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 20172144.

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 3 ways as a sum of consecutive naturals, for example, 210079 + ... + 210174.

Almost surely, 2^20172144 is an apocalyptic number.

20172144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20172144 is an abundant number, since it is smaller than the sum of its proper divisors (31939352).

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

20172144 is a wasteful number, since it uses less digits than its factorization.

20172144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420264 (or 420258 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 20172144 is about 4491.3410024179. The cubic root of 20172144 is about 272.2183224085.

Adding to 20172144 its reverse (44127102), we get a palindrome (64299246).

The spelling of 20172144 in words is "twenty million, one hundred seventy-two thousand, one hundred forty-four".