21043600 has 30 divisors (see below), whose sum is σ = 50558210. Its totient is φ = 8417280.

The previous prime is 21043591. The next prime is 21043609. The reversal of 21043600 is 634012.

It is an interprime number because it is at equal distance from previous prime (21043591) and next prime (21043609).

It can be written as a sum of positive squares in 3 ways, for example, as 5456896 + 15586704 = 2336^2 + 3948^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (21043609) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25905 + ... + 26704.

Almost surely, 2^21043600 is an apocalyptic number.

21043600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043600 is an abundant number, since it is smaller than the sum of its proper divisors (29514610).

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

21043600 is a wasteful number, since it uses less digits than its factorization.

21043600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52627 (or 52616 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21043600 is about 4587.3303783355. The cubic root of 21043600 is about 276.0832207211.

Adding to 21043600 its reverse (634012), we get a palindrome (21677612).

The spelling of 21043600 in words is "twenty-one million, forty-three thousand, six hundred".