21102800 has 30 divisors (see below), whose sum is σ = 50700438. Its totient is φ = 8440960.

The previous prime is 21102761. The next prime is 21102821. The reversal of 21102800 is 820112.

It can be written as a sum of positive squares in 3 ways, for example, as 4227136 + 16875664 = 2056^2 + 4108^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25979 + ... + 26778.

Almost surely, 2^21102800 is an apocalyptic number.

21102800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102800 is an abundant number, since it is smaller than the sum of its proper divisors (29597638).

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

21102800 is a wasteful number, since it uses less digits than its factorization.

21102800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52775 (or 52764 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 21102800 is about 4593.7784012727. The cubic root of 21102800 is about 276.3418713973.

Adding to 21102800 its reverse (820112), we get a palindrome (21922912).

The spelling of 21102800 in words is "twenty-one million, one hundred two thousand, eight hundred".