21316724 has 48 divisors (see below), whose sum is σ = 44452800. Its totient is φ = 8816640.

The previous prime is 21316723. The next prime is 21316739. The reversal of 21316724 is 42761312.

It is a Harshad number since it is a multiple of its sum of digits (26).

21316724 is a Rhonda number in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 21316693 and 21316702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47252 + ... + 47700.

It is an arithmetic number, because the mean of its divisors is an integer number (926100).

Almost surely, 2^21316724 is an apocalyptic number.

It is an amenable number.

21316724 is an abundant number, since it is smaller than the sum of its proper divisors (23136076).

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

21316724 is a wasteful number, since it uses less digits than its factorization.

21316724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560 (or 558 counting only the distinct ones).

The product of its digits is 2016, while the sum is 26.

The square root of 21316724 is about 4617.0037903385. The cubic root of 21316724 is about 277.2725143744.

The spelling of 21316724 in words is "twenty-one million, three hundred sixteen thousand, seven hundred twenty-four".