21534984 has 80 divisors (see below), whose sum is σ = 60984000. Its totient is φ = 7099488.

The previous prime is 21534983. The next prime is 21534991. The reversal of 21534984 is 48943512.

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

Its product of digits (34560) is a multiple of the sum of its prime factors (384).

It is not an unprimeable number, because it can be changed into a prime (21534983) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 108117 + ... + 108315.

It is an arithmetic number, because the mean of its divisors is an integer number (762300).

Almost surely, 2^21534984 is an apocalyptic number.

21534984 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 21534984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30492000).

21534984 is an abundant number, since it is smaller than the sum of its proper divisors (39449016).

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

21534984 is a wasteful number, since it uses less digits than its factorization.

21534984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 371 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21534984 is about 4640.5801361468. The cubic root of 21534984 is about 278.2156255442.

The spelling of 21534984 in words is "twenty-one million, five hundred thirty-four thousand, nine hundred eighty-four".