21424944 has 20 divisors (see below), whose sum is σ = 55347896. Its totient is φ = 7141632.

The previous prime is 21424943. The next prime is 21424957. The reversal of 21424944 is 44942412.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223129 + ... + 223224.

Almost surely, 2^21424944 is an apocalyptic number.

21424944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21424944 is an abundant number, since it is smaller than the sum of its proper divisors (33922952).

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

21424944 is a wasteful number, since it uses less digits than its factorization.

21424944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446364 (or 446358 counting only the distinct ones).

The product of its digits is 9216, while the sum is 30.

The square root of 21424944 is about 4628.7086752139. The cubic root of 21424944 is about 277.7409383797.

The spelling of 21424944 in words is "twenty-one million, four hundred twenty-four thousand, nine hundred forty-four".