21965665 has 8 divisors (see below), whose sum is σ = 26392320. Its totient is φ = 17550192.

The previous prime is 21965659. The next prime is 21965681. The reversal of 21965665 is 56656912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21965665 - 2¹³ = 21957473 is a prime.

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 7 ways as a sum of consecutive naturals, for example, 2416 + ... + 7054.

It is an arithmetic number, because the mean of its divisors is an integer number (3299040).

Almost surely, 2^21965665 is an apocalyptic number.

It is an amenable number.

21965665 is a deficient number, since it is larger than the sum of its proper divisors (4426655).

21965665 is an equidigital number, since it uses as much as digits as its factorization.

21965665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5591.

The product of its digits is 97200, while the sum is 40.

The square root of 21965665 is about 4686.7542073380. The cubic root of 21965665 is about 280.0580874384.

The spelling of 21965665 in words is "twenty-one million, nine hundred sixty-five thousand, six hundred sixty-five".