20722520 has 64 divisors (see below), whose sum is σ = 57395520. Its totient is φ = 6557184.

The previous prime is 20722519. The next prime is 20722543. The reversal of 20722520 is 2522702.

20722520 = 128² + 129² + ... + 400².

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 20722492 and 20722501.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 794 + ... + 6486.

It is an arithmetic number, because the mean of its divisors is an integer number (896805).

Almost surely, 2^20722520 is an apocalyptic number.

20722520 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 20722520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28697760).

20722520 is an abundant number, since it is smaller than the sum of its proper divisors (36673000).

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

20722520 is a wasteful number, since it uses less digits than its factorization.

20722520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5724 (or 5720 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 20.

The square root of 20722520 is about 4552.1994683889. The cubic root of 20722520 is about 274.6718731012.

The spelling of 20722520 in words is "twenty million, seven hundred twenty-two thousand, five hundred twenty".