21122500 has 120 divisors (see below), whose sum is σ = 56681856. Its totient is φ = 6720000.

The previous prime is 21122473. The next prime is 21122561. The reversal of 21122500 is 522112.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 297465 + ... + 297535.

Almost surely, 2^21122500 is an apocalyptic number.

21122500 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 21122500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28340928).

21122500 is an abundant number, since it is smaller than the sum of its proper divisors (35559356).

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

21122500 is a wasteful number, since it uses less digits than its factorization.

21122500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21122500 is about 4595.9221055192. The cubic root of 21122500 is about 276.4278353725.

Adding to 21122500 its reverse (522112), we get a palindrome (21644612).

The spelling of 21122500 in words is "twenty-one million, one hundred twenty-two thousand, five hundred".