21909117 has 8 divisors (see below), whose sum is σ = 29340640. Its totient is φ = 14541840.

The previous prime is 21909103. The next prime is 21909131. The reversal of 21909117 is 71190912.

It is an interprime number because it is at equal distance from previous prime (21909103) and next prime (21909131).

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

It is not a de Polignac number, because 21909117 - 2⁴ = 21909101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21909817) 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, 15259 + ... + 16632.

It is an arithmetic number, because the mean of its divisors is an integer number (3667580).

Almost surely, 2^21909117 is an apocalyptic number.

It is an amenable number.

21909117 is a deficient number, since it is larger than the sum of its proper divisors (7431523).

21909117 is a wasteful number, since it uses less digits than its factorization.

21909117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32123.

The product of its (nonzero) digits is 1134, while the sum is 30.

The square root of 21909117 is about 4680.7175731932. The cubic root of 21909117 is about 279.8175554669.

The spelling of 21909117 in words is "twenty-one million, nine hundred nine thousand, one hundred seventeen".