21318965 has 16 divisors (see below), whose sum is σ = 26466048. Its totient is φ = 16476096.

The previous prime is 21318961. The next prime is 21318967. The reversal of 21318965 is 56981312.

It is a cyclic number.

It is not a de Polignac number, because 21318965 - 2² = 21318961 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318961) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18959 + ... + 20051.

It is an arithmetic number, because the mean of its divisors is an integer number (1654128).

Almost surely, 2^21318965 is an apocalyptic number.

It is an amenable number.

21318965 is a deficient number, since it is larger than the sum of its proper divisors (5147083).

21318965 is a wasteful number, since it uses less digits than its factorization.

21318965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1228.

The product of its digits is 12960, while the sum is 35.

The square root of 21318965 is about 4617.2464738197. The cubic root of 21318965 is about 277.2822304692.

The spelling of 21318965 in words is "twenty-one million, three hundred eighteen thousand, nine hundred sixty-five".