21722940 has 144 divisors (see below), whose sum is σ = 72334080. Its totient is φ = 5253120.

The previous prime is 21722933. The next prime is 21722963. The reversal of 21722940 is 4922712.

It is a super-2 number, since 2×21722940² = 943772244487200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 94746 + ... + 94974.

It is an arithmetic number, because the mean of its divisors is an integer number (502320).

Almost surely, 2^21722940 is an apocalyptic number.

21722940 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 21722940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36167040).

21722940 is an abundant number, since it is smaller than the sum of its proper divisors (50611140).

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

21722940 is a wasteful number, since it uses less digits than its factorization.

21722940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21722940 is about 4660.7874871099. The cubic root of 21722940 is about 279.0226982728.

The spelling of 21722940 in words is "twenty-one million, seven hundred twenty-two thousand, nine hundred forty".