21723464 has 48 divisors (see below), whose sum is σ = 47825280. Its totient is φ = 9223200.

The previous prime is 21723463. The next prime is 21723469. The reversal of 21723464 is 46432712.

It is not an unprimeable number, because it can be changed into a prime (21723463) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59009 + ... + 59375.

It is an arithmetic number, because the mean of its divisors is an integer number (996360).

Almost surely, 2^21723464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21723464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23912640).

21723464 is an abundant number, since it is smaller than the sum of its proper divisors (26101816).

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

21723464 is a wasteful number, since it uses less digits than its factorization.

21723464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538 (or 527 counting only the distinct ones).

The product of its digits is 8064, while the sum is 29.

The square root of 21723464 is about 4660.8437004474. The cubic root of 21723464 is about 279.0249417800.

The spelling of 21723464 in words is "twenty-one million, seven hundred twenty-three thousand, four hundred sixty-four".