20722172 has 12 divisors (see below), whose sum is σ = 37840656. Its totient is φ = 9910560.

The previous prime is 20722171. The next prime is 20722181. The reversal of 20722172 is 27122702.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20722171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112529 + ... + 112712.

It is an arithmetic number, because the mean of its divisors is an integer number (3153388).

Almost surely, 2^20722172 is an apocalyptic number.

It is an amenable number.

20722172 is a deficient number, since it is larger than the sum of its proper divisors (17118484).

20722172 is a wasteful number, since it uses less digits than its factorization.

20722172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225268 (or 225266 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 20722172 is about 4552.1612449473. The cubic root of 20722172 is about 274.6703355413.

Adding to 20722172 its reverse (27122702), we get a palindrome (47844874).

The spelling of 20722172 in words is "twenty million, seven hundred twenty-two thousand, one hundred seventy-two".