21534744 has 128 divisors (see below), whose sum is σ = 68935680. Its totient is φ = 5443200.

The previous prime is 21534743. The next prime is 21534757. The reversal of 21534744 is 44743512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21534743) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79329 + ... + 79599.

It is an arithmetic number, because the mean of its divisors is an integer number (538560).

Almost surely, 2^21534744 is an apocalyptic number.

21534744 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 21534744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34467840).

21534744 is an abundant number, since it is smaller than the sum of its proper divisors (47400936).

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

21534744 is a wasteful number, since it uses less digits than its factorization.

21534744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341 (or 337 counting only the distinct ones).

The product of its digits is 13440, while the sum is 30.

The square root of 21534744 is about 4640.5542772389. The cubic root of 21534744 is about 278.2145920011.

The spelling of 21534744 in words is "twenty-one million, five hundred thirty-four thousand, seven hundred forty-four".