21018960 has 160 divisors (see below), whose sum is σ = 74638080. Its totient is φ = 5432832.

The previous prime is 21018947. The next prime is 21018967. The reversal of 21018960 is 6981012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018967) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79789 + ... + 80051.

It is an arithmetic number, because the mean of its divisors is an integer number (466488).

Almost surely, 2^21018960 is an apocalyptic number.

21018960 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 21018960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37319040).

21018960 is an abundant number, since it is smaller than the sum of its proper divisors (53619120).

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

21018960 is a wasteful number, since it uses less digits than its factorization.

21018960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 21018960 is about 4584.6439338295. The cubic root of 21018960 is about 275.9754231424.

Adding to 21018960 its reverse (6981012), we get a palindrome (27999972).

The spelling of 21018960 in words is "twenty-one million, eighteen thousand, nine hundred sixty".