21444744 has 32 divisors (see below), whose sum is σ = 53759520. Its totient is φ = 7128576.

The previous prime is 21444739. The next prime is 21444751. The reversal of 21444744 is 44744412.

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9624 + ... + 11640.

It is an arithmetic number, because the mean of its divisors is an integer number (1679985).

Almost surely, 2^21444744 is an apocalyptic number.

21444744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21444744 is an abundant number, since it is smaller than the sum of its proper divisors (32314776).

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

21444744 is a wasteful number, since it uses less digits than its factorization.

21444744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2469 (or 2465 counting only the distinct ones).

The product of its digits is 14336, while the sum is 30.

The square root of 21444744 is about 4630.8470067581. The cubic root of 21444744 is about 277.8264707291.

The spelling of 21444744 in words is "twenty-one million, four hundred forty-four thousand, seven hundred forty-four".