21669109 has 16 divisors (see below), whose sum is σ = 27127296. Its totient is φ = 16815600.

The previous prime is 21669079. The next prime is 21669113. The reversal of 21669109 is 90196612.

It is a cyclic number.

It is not a de Polignac number, because 21669109 - 2⁵ = 21669077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21669149) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 26314 + ... + 27124.

It is an arithmetic number, because the mean of its divisors is an integer number (1695456).

Almost surely, 2^21669109 is an apocalyptic number.

It is an amenable number.

21669109 is a deficient number, since it is larger than the sum of its proper divisors (5458187).

21669109 is a wasteful number, since it uses less digits than its factorization.

21669109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 21669109 is about 4655.0090225476. The cubic root of 21669109 is about 278.7920282236.

The spelling of 21669109 in words is "twenty-one million, six hundred sixty-nine thousand, one hundred nine".