21371600 has 90 divisors (see below), whose sum is σ = 54206166. Its totient is φ = 8096000.

The previous prime is 21371591. The next prime is 21371627. The reversal of 21371600 is 617312.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 5721664 + 15649936 = 2392^2 + 3956^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 211550 + ... + 211650.

Almost surely, 2^21371600 is an apocalyptic number.

21371600 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 21371600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27103083).

21371600 is an abundant number, since it is smaller than the sum of its proper divisors (32834566).

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

21371600 is a wasteful number, since it uses less digits than its factorization.

21371600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 21371600 is about 4622.9427857156. The cubic root of 21371600 is about 277.5102395919.

Adding to 21371600 its reverse (617312), we get a palindrome (21988912).

The spelling of 21371600 in words is "twenty-one million, three hundred seventy-one thousand, six hundred".