21485808 has 60 divisors (see below), whose sum is σ = 63303240. Its totient is φ = 6784128.

The previous prime is 21485803. The next prime is 21485809. The reversal of 21485808 is 80858412.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21485803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1191 + ... + 6662.

It is an arithmetic number, because the mean of its divisors is an integer number (1055054).

Almost surely, 2^21485808 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 21485808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31651620).

21485808 is an abundant number, since it is smaller than the sum of its proper divisors (41817432).

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

21485808 is a wasteful number, since it uses less digits than its factorization.

21485808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7886 (or 7877 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 21485808 is about 4635.2786324017. The cubic root of 21485808 is about 278.0036919614.

The spelling of 21485808 in words is "twenty-one million, four hundred eighty-five thousand, eight hundred eight".