21133404 has 36 divisors (see below), whose sum is σ = 53604096. Its totient is φ = 7020288.

The previous prime is 21133403. The next prime is 21133423. The reversal of 21133404 is 40433112.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11877 + ... + 13539.

Almost surely, 2^21133404 is an apocalyptic number.

It is an amenable number.

21133404 is an abundant number, since it is smaller than the sum of its proper divisors (32470692).

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

21133404 is a wasteful number, since it uses less digits than its factorization.

21133404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2026 (or 2021 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21133404 is about 4597.1082214801. The cubic root of 21133404 is about 276.4753936729.

Adding to 21133404 its reverse (40433112), we get a palindrome (61566516).

The spelling of 21133404 in words is "twenty-one million, one hundred thirty-three thousand, four hundred four".