21032100 has 54 divisors (see below), whose sum is σ = 65926770. Its totient is φ = 5608320.

The previous prime is 21032087. The next prime is 21032119. The reversal of 21032100 is 123012.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 19044 + 21013056 = 138^2 + 4584^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

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, 10785 + ... + 12584.

Almost surely, 2^21032100 is an apocalyptic number.

21032100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21032100 is an abundant number, since it is smaller than the sum of its proper divisors (44894670).

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

21032100 is a wasteful number, since it uses less digits than its factorization.

21032100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23389 (or 23379 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21032100 is about 4586.0767547000. The cubic root of 21032100 is about 276.0329198289.

Adding to 21032100 its reverse (123012), we get a palindrome (21155112).

The spelling of 21032100 in words is "twenty-one million, thirty-two thousand, one hundred".