21133400 has 24 divisors (see below), whose sum is σ = 49135620. Its totient is φ = 8453280.

The previous prime is 21133381. The next prime is 21133403. The reversal of 21133400 is 433112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133403) 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, 52634 + ... + 53033.

Almost surely, 2^21133400 is an apocalyptic number.

21133400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21133400 is an abundant number, since it is smaller than the sum of its proper divisors (28002220).

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

21133400 is a wasteful number, since it uses less digits than its factorization.

21133400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105683 (or 105674 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21133400 is about 4597.1077864240. The cubic root of 21133400 is about 276.4753762297.

Adding to 21133400 its reverse (433112), we get a palindrome (21566512).

The spelling of 21133400 in words is "twenty-one million, one hundred thirty-three thousand, four hundred".