21902109 has 8 divisors (see below), whose sum is σ = 29225952. Its totient is φ = 14589840.

The previous prime is 21902107. The next prime is 21902119. The reversal of 21902109 is 90120912.

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

It is not a de Polignac number, because 21902109 - 2¹ = 21902107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21902107) 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, 3622 + ... + 7544.

It is an arithmetic number, because the mean of its divisors is an integer number (3653244).

Almost surely, 2^21902109 is an apocalyptic number.

It is an amenable number.

21902109 is a deficient number, since it is larger than the sum of its proper divisors (7323843).

21902109 is a wasteful number, since it uses less digits than its factorization.

21902109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5787.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 21902109 is about 4679.9689101531. The cubic root of 21902109 is about 279.7877174997.

The spelling of 21902109 in words is "twenty-one million, nine hundred two thousand, one hundred nine".