21965259 has 4 divisors (see below), whose sum is σ = 29287016. Its totient is φ = 14643504.

The previous prime is 21965249. The next prime is 21965351. The reversal of 21965259 is 95256912.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21965259 - 2⁴ = 21965243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21965219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3660874 + ... + 3660879.

It is an arithmetic number, because the mean of its divisors is an integer number (7321754).

Almost surely, 2^21965259 is an apocalyptic number.

21965259 is a deficient number, since it is larger than the sum of its proper divisors (7321757).

21965259 is an equidigital number, since it uses as much as digits as its factorization.

21965259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7321756.

The product of its digits is 48600, while the sum is 39.

The square root of 21965259 is about 4686.7108935798. The cubic root of 21965259 is about 280.0563619533.

The spelling of 21965259 in words is "twenty-one million, nine hundred sixty-five thousand, two hundred fifty-nine".