21722580 has 240 divisors, whose sum is σ = 79035264. Its totient is φ = 4942080.

The previous prime is 21722543. The next prime is 21722587. The reversal of 21722580 is 8522712.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722587) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 409834 + ... + 409886.

Almost surely, 2^21722580 is an apocalyptic number.

21722580 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 21722580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39517632).

21722580 is an abundant number, since it is smaller than the sum of its proper divisors (57312684).

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

21722580 is a wasteful number, since it uses less digits than its factorization.

21722580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21722580 is about 4660.7488668668. The cubic root of 21722580 is about 279.0211569110.

The spelling of 21722580 in words is "twenty-one million, seven hundred twenty-two thousand, five hundred eighty".