21012600 has 96 divisors (see below), whose sum is σ = 74459520. Its totient is φ = 4801920.

The previous prime is 21012599. The next prime is 21012647. The reversal of 21012600 is 621012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1699 + ... + 6701.

It is an arithmetic number, because the mean of its divisors is an integer number (775620).

Almost surely, 2^21012600 is an apocalyptic number.

21012600 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 21012600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37229760).

21012600 is an abundant number, since it is smaller than the sum of its proper divisors (53446920).

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

21012600 is a wasteful number, since it uses less digits than its factorization.

21012600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5029 (or 5020 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21012600 is about 4583.9502615103. The cubic root of 21012600 is about 275.9475850896.

Adding to 21012600 its reverse (621012), we get a palindrome (21633612).

It can be divided in two parts, 21012 and 600, that added together give a palindrome (21612).

The spelling of 21012600 in words is "twenty-one million, twelve thousand, six hundred".