21966315 has 16 divisors (see below), whose sum is σ = 40167168. Its totient is φ = 10041696.

The previous prime is 21966313. The next prime is 21966317. The reversal of 21966315 is 51366912.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21966313) and next prime (21966317).

It is not a de Polignac number, because 21966315 - 2¹ = 21966313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21966313) 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, 104497 + ... + 104706.

It is an arithmetic number, because the mean of its divisors is an integer number (2510448).

Almost surely, 2^21966315 is an apocalyptic number.

21966315 is a deficient number, since it is larger than the sum of its proper divisors (18200853).

21966315 is a wasteful number, since it uses less digits than its factorization.

21966315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209218.

The product of its digits is 9720, while the sum is 33.

The square root of 21966315 is about 4686.8235511911. The cubic root of 21966315 is about 280.0608498703.

The spelling of 21966315 in words is "twenty-one million, nine hundred sixty-six thousand, three hundred fifteen".