21626880 has 144 divisors (see below), whose sum is σ = 75497184. Its totient is φ = 5242880.

The previous prime is 21626819. The next prime is 21626881. The reversal of 21626880 is 8862612.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21626881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1966075 + ... + 1966085.

It is an arithmetic number, because the mean of its divisors is an integer number (524286).

Almost surely, 2^21626880 is an apocalyptic number.

21626880 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 21626880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37748592).

21626880 is an abundant number, since it is smaller than the sum of its proper divisors (53870304).

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

21626880 is an frugal number, since it uses more digits than its factorization.

21626880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53 (or 21 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 21626880 is about 4650.4709438937. The cubic root of 21626880 is about 278.6108061176.

The spelling of 21626880 in words is "twenty-one million, six hundred twenty-six thousand, eight hundred eighty".