21669365 has 8 divisors (see below), whose sum is σ = 26202528. Its totient is φ = 17202640.

The previous prime is 21669353. The next prime is 21669371. The reversal of 21669365 is 56396612.

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

It is not a de Polignac number, because 21669365 - 2²⁴ = 4892149 is a prime.

It is a super-2 number, since 2×21669365² = 939122759006450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15887 + ... + 17196.

It is an arithmetic number, because the mean of its divisors is an integer number (3275316).

Almost surely, 2^21669365 is an apocalyptic number.

It is an amenable number.

21669365 is a deficient number, since it is larger than the sum of its proper divisors (4533163).

21669365 is a wasteful number, since it uses less digits than its factorization.

21669365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33219.

The product of its digits is 58320, while the sum is 38.

The square root of 21669365 is about 4655.0365197279. The cubic root of 21669365 is about 278.7931261072.

The spelling of 21669365 in words is "twenty-one million, six hundred sixty-nine thousand, three hundred sixty-five".