21969315 has 12 divisors (see below), whose sum is σ = 38080224. Its totient is φ = 11716944.

The previous prime is 21969313. The next prime is 21969331. The reversal of 21969315 is 51396912.

It is not a de Polignac number, because 21969315 - 2¹ = 21969313 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21969315.

It is not an unprimeable number, because it can be changed into a prime (21969313) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 244059 + ... + 244148.

It is an arithmetic number, because the mean of its divisors is an integer number (3173352).

Almost surely, 2^21969315 is an apocalyptic number.

21969315 is a deficient number, since it is larger than the sum of its proper divisors (16110909).

21969315 is a wasteful number, since it uses less digits than its factorization.

21969315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488218 (or 488215 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 21969315 is about 4687.1435864501. The cubic root of 21969315 is about 280.0735988499.

It can be divided in two parts, 2196 and 9315, that added together give a palindrome (11511).

The spelling of 21969315 in words is "twenty-one million, nine hundred sixty-nine thousand, three hundred fifteen".