21621200 has 60 divisors (see below), whose sum is σ = 52401408. Its totient is φ = 8572800.

The previous prime is 21621181. The next prime is 21621233. The reversal of 21621200 is 212612.

It is a congruent number.

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, 76259 + ... + 76541.

Almost surely, 2^21621200 is an apocalyptic number.

21621200 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 21621200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26200704).

21621200 is an abundant number, since it is smaller than the sum of its proper divisors (30780208).

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

21621200 is a wasteful number, since it uses less digits than its factorization.

21621200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 481 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21621200 is about 4649.8602129526. The cubic root of 21621200 is about 278.5864128942.

Adding to 21621200 its reverse (212612), we get a palindrome (21833812).

The spelling of 21621200 in words is "twenty-one million, six hundred twenty-one thousand, two hundred".