21488544 has 384 divisors, whose sum is σ = 87091200. Its totient is φ = 4976640.

The previous prime is 21488543. The next prime is 21488557. The reversal of 21488544 is 44588412.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21488499 and 21488508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21488543) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1130967 + ... + 1130985.

It is an arithmetic number, because the mean of its divisors is an integer number (226800).

Almost surely, 2^21488544 is an apocalyptic number.

21488544 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 21488544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43545600).

21488544 is an abundant number, since it is smaller than the sum of its proper divisors (65602656).

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

21488544 is a wasteful number, since it uses less digits than its factorization.

21488544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 59 counting only the distinct ones).

The product of its digits is 40960, while the sum is 36.

The square root of 21488544 is about 4635.5737508964. The cubic root of 21488544 is about 278.0154917785.

The spelling of 21488544 in words is "twenty-one million, four hundred eighty-eight thousand, five hundred forty-four".