21022400 has 84 divisors (see below), whose sum is σ = 59149488. Its totient is φ = 7203840.

The previous prime is 21022373. The next prime is 21022411. The reversal of 21022400 is 422012.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10262 + ... + 12138.

Almost surely, 2^21022400 is an apocalyptic number.

21022400 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 21022400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29574744).

21022400 is an abundant number, since it is smaller than the sum of its proper divisors (38127088).

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

21022400 is a wasteful number, since it uses less digits than its factorization.

21022400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1906 (or 1891 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 21022400 is about 4585.0190839297. The cubic root of 21022400 is about 275.9904778623.

Adding to 21022400 its reverse (422012), we get a palindrome (21444412).

The spelling of 21022400 in words is "twenty-one million, twenty-two thousand, four hundred".