21485984 has 72 divisors (see below), whose sum is σ = 47730060. Its totient is φ = 9504768.

The previous prime is 21485957. The next prime is 21485993. The reversal of 21485984 is 48958412.

It can be written as a sum of positive squares in 6 ways, for example, as 4080400 + 17405584 = 2020^2 + 4172^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 156764 + ... + 156900.

Almost surely, 2^21485984 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 21485984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23865030).

21485984 is an abundant number, since it is smaller than the sum of its proper divisors (26244076).

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

21485984 is a wasteful number, since it uses less digits than its factorization.

21485984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 181 counting only the distinct ones).

The product of its digits is 92160, while the sum is 41.

The square root of 21485984 is about 4635.2976171978. The cubic root of 21485984 is about 278.0044510441.

The spelling of 21485984 in words is "twenty-one million, four hundred eighty-five thousand, nine hundred eighty-four".