21929109 has 8 divisors (see below), whose sum is σ = 29332320. Its totient is φ = 14572656.

The previous prime is 21929107. The next prime is 21929129. The reversal of 21929109 is 90192912.

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

It is not a de Polignac number, because 21929109 - 2¹ = 21929107 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21929109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929101) 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 7 ways as a sum of consecutive naturals, for example, 10579 + ... + 12480.

It is an arithmetic number, because the mean of its divisors is an integer number (3666540).

Almost surely, 2^21929109 is an apocalyptic number.

It is an amenable number.

21929109 is a deficient number, since it is larger than the sum of its proper divisors (7403211).

21929109 is a wasteful number, since it uses less digits than its factorization.

21929109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23379.

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 21929109 is about 4682.8526562342. The cubic root of 21929109 is about 279.9026404705.

The spelling of 21929109 in words is "twenty-one million, nine hundred twenty-nine thousand, one hundred nine".