21252100 has 27 divisors (see below), whose sum is σ = 46217311. Its totient is φ = 8482400.

The previous prime is 21252079. The next prime is 21252107. The reversal of 21252100 is 125212.

The square root of 21252100 is 4610.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 2172676 + 19079424 = 1474^2 + 4368^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252107) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 45870 + ... + 46330.

Almost surely, 2^21252100 is an apocalyptic number.

21252100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21252100 is the 4610-th square number.

It is an amenable number.

21252100 is an abundant number, since it is smaller than the sum of its proper divisors (24965211).

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

21252100 is an equidigital number, since it uses as much as digits as its factorization.

21252100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936 (or 468 counting only the distinct ones).

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

The cubic root of 21252100 is about 276.9920366802.

Adding to 21252100 its reverse (125212), we get a palindrome (21377312).

It can be divided in two parts, 2125 and 2100, that added together give a square (4225 = 65²).

The spelling of 21252100 in words is "twenty-one million, two hundred fifty-two thousand, one hundred".