21445669 has 8 divisors (see below), whose sum is σ = 24584768. Its totient is φ = 18325440.

The previous prime is 21445657. The next prime is 21445673. The reversal of 21445669 is 96654412.

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

It is not a de Polignac number, because 21445669 - 2⁹ = 21445157 is a prime.

It is a super-2 number, since 2×21445669² = 919833437715122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2187 + ... + 6904.

It is an arithmetic number, because the mean of its divisors is an integer number (3073096).

Almost surely, 2^21445669 is an apocalyptic number.

It is an amenable number.

21445669 is a deficient number, since it is larger than the sum of its proper divisors (3139099).

21445669 is an equidigital number, since it uses as much as digits as its factorization.

21445669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9435.

The product of its digits is 51840, while the sum is 37.

The square root of 21445669 is about 4630.9468794189. The cubic root of 21445669 is about 277.8304652711.

The spelling of 21445669 in words is "twenty-one million, four hundred forty-five thousand, six hundred sixty-nine".