20972220 has 96 divisors (see below), whose sum is σ = 64411200. Its totient is φ = 5074944.

The previous prime is 20972179. The next prime is 20972221. The reversal of 20972220 is 2227902.

20972220 = 306² + 307² + ... + 450².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20972221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29226 + ... + 29934.

It is an arithmetic number, because the mean of its divisors is an integer number (670950).

Almost surely, 2^20972220 is an apocalyptic number.

20972220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20972220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32205600).

20972220 is an abundant number, since it is smaller than the sum of its proper divisors (43438980).

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

20972220 is a wasteful number, since it uses less digits than its factorization.

20972220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 20972220 is about 4579.5436453865. The cubic root of 20972220 is about 275.7707085360.

The spelling of 20972220 in words is "twenty million, nine hundred seventy-two thousand, two hundred twenty".