21260940 has 96 divisors (see below), whose sum is σ = 62537664. Its totient is φ = 5391360.

The previous prime is 21260917. The next prime is 21260971. The reversal of 21260940 is 4906212.

It is a zygodrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 21260940.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135342 + ... + 135498.

It is an arithmetic number, because the mean of its divisors is an integer number (651434).

Almost surely, 2^21260940 is an apocalyptic number.

21260940 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 21260940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31268832).

21260940 is an abundant number, since it is smaller than the sum of its proper divisors (41276724).

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

21260940 is a wasteful number, since it uses less digits than its factorization.

21260940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21260940 is about 4610.9586855664. The cubic root of 21260940 is about 277.0304371234.

The spelling of 21260940 in words is "twenty-one million, two hundred sixty thousand, nine hundred forty".