21424344 has 32 divisors (see below), whose sum is σ = 53680320. Its totient is φ = 7125536.

The previous prime is 21424327. The next prime is 21424357. The reversal of 21424344 is 44342412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 15739 + ... + 17045.

It is an arithmetic number, because the mean of its divisors is an integer number (1677510).

Almost surely, 2^21424344 is an apocalyptic number.

21424344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21424344 is an abundant number, since it is smaller than the sum of its proper divisors (32255976).

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

21424344 is a wasteful number, since it uses less digits than its factorization.

21424344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1999 (or 1995 counting only the distinct ones).

The product of its digits is 3072, while the sum is 24.

The square root of 21424344 is about 4628.6438618671. The cubic root of 21424344 is about 277.7383456678.

Adding to 21424344 its reverse (44342412), we get a palindrome (65766756).

The spelling of 21424344 in words is "twenty-one million, four hundred twenty-four thousand, three hundred forty-four".