21424704 has 112 divisors (see below), whose sum is σ = 68275200. Its totient is φ = 5792256.

The previous prime is 21424699. The next prime is 21424759. The reversal of 21424704 is 40742412.

It is a tau number, because it is divible by the number of its divisors (112).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25117 + ... + 25955.

It is an arithmetic number, because the mean of its divisors is an integer number (609600).

Almost surely, 2^21424704 is an apocalyptic number.

21424704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21424704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34137600).

21424704 is an abundant number, since it is smaller than the sum of its proper divisors (46850496).

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

21424704 is a wasteful number, since it uses less digits than its factorization.

21424704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880 (or 870 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21424704 is about 4628.6827499841. The cubic root of 21424704 is about 277.7399013008.

The spelling of 21424704 in words is "twenty-one million, four hundred twenty-four thousand, seven hundred four".