21549960 has 96 divisors (see below), whose sum is σ = 72334080. Its totient is φ = 5558400.

The previous prime is 21549953. The next prime is 21549961. The reversal of 21549960 is 6994512.

21549960 is a `hidden beast` number, since 21 + 549 + 96 + 0 = 666.

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

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (21549961) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10195 + ... + 12125.

It is an arithmetic number, because the mean of its divisors is an integer number (753480).

Almost surely, 2^21549960 is an apocalyptic number.

21549960 is a gapful number since it is divisible by the number (20) 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 21549960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36167040).

21549960 is an abundant number, since it is smaller than the sum of its proper divisors (50784120).

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

21549960 is a wasteful number, since it uses less digits than its factorization.

21549960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1979 (or 1972 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 21549960 is about 4642.1934470679. The cubic root of 21549960 is about 278.2801034457.

The spelling of 21549960 in words is "twenty-one million, five hundred forty-nine thousand, nine hundred sixty".