21360400 has 30 divisors (see below), whose sum is σ = 51319322. Its totient is φ = 8544000.

The previous prime is 21360377. The next prime is 21360401. The reversal of 21360400 is 406312.

It can be written as a sum of positive squares in 3 ways, for example, as 126736 + 21233664 = 356^2 + 4608^2 .

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 (21360401) 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, 26301 + ... + 27100.

Almost surely, 2^21360400 is an apocalyptic number.

21360400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21360400 is an abundant number, since it is smaller than the sum of its proper divisors (29958922).

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

21360400 is a wasteful number, since it uses less digits than its factorization.

21360400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53419 (or 53408 counting only the distinct ones).

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

The square root of 21360400 is about 4621.7312773462. The cubic root of 21360400 is about 277.4617537853.

Adding to 21360400 its reverse (406312), we get a palindrome (21766712).

The spelling of 21360400 in words is "twenty-one million, three hundred sixty thousand, four hundred".