21969065 has 4 divisors (see below), whose sum is σ = 26362884. Its totient is φ = 17575248.

The previous prime is 21969029. The next prime is 21969091. The reversal of 21969065 is 56096912.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12033961 + 9935104 = 3469^2 + 3152^2 .

It is a cyclic number.

It is not a de Polignac number, because 21969065 - 2¹⁸ = 21706921 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2196902 + ... + 2196911.

It is an arithmetic number, because the mean of its divisors is an integer number (6590721).

Almost surely, 2^21969065 is an apocalyptic number.

It is an amenable number.

21969065 is a deficient number, since it is larger than the sum of its proper divisors (4393819).

21969065 is an equidigital number, since it uses as much as digits as its factorization.

21969065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4393818.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 21969065 is about 4687.1169176798. The cubic root of 21969065 is about 280.0725364793.

The spelling of 21969065 in words is "twenty-one million, nine hundred sixty-nine thousand, sixty-five".