21404844 has 24 divisors (see below), whose sum is σ = 55494320. Its totient is φ = 7134912.

The previous prime is 21404843. The next prime is 21404857. The reversal of 21404844 is 44840412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21404843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98989 + ... + 99204.

Almost surely, 2^21404844 is an apocalyptic number.

It is an amenable number.

21404844 is an abundant number, since it is smaller than the sum of its proper divisors (34089476).

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

21404844 is a wasteful number, since it uses less digits than its factorization.

21404844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198206 (or 198198 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 27.

The square root of 21404844 is about 4626.5369338199. The cubic root of 21404844 is about 277.6540561680.

The spelling of 21404844 in words is "twenty-one million, four hundred four thousand, eight hundred forty-four".