21318885 has 24 divisors (see below), whose sum is σ = 42232320. Its totient is φ = 9745632.

The previous prime is 21318881. The next prime is 21318889. The reversal of 21318885 is 58881312.

It is an interprime number because it is at equal distance from previous prime (21318881) and next prime (21318889).

It is not a de Polignac number, because 21318885 - 2² = 21318881 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318881) 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, 33525 + ... + 34154.

It is an arithmetic number, because the mean of its divisors is an integer number (1759680).

Almost surely, 2^21318885 is an apocalyptic number.

It is an amenable number.

21318885 is a deficient number, since it is larger than the sum of its proper divisors (20913435).

21318885 is a wasteful number, since it uses less digits than its factorization.

21318885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67697 (or 67694 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 21318885 is about 4617.2378106396. The cubic root of 21318885 is about 277.2818836324.

The spelling of 21318885 in words is "twenty-one million, three hundred eighteen thousand, eight hundred eighty-five".