21912117 has 8 divisors (see below), whose sum is σ = 29500224. Its totient is φ = 14466048.

The previous prime is 21912101. The next prime is 21912157. The reversal of 21912117 is 71121912.

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

It is not a de Polignac number, because 21912117 - 2⁴ = 21912101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21912157) 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, 35148 + ... + 35765.

It is an arithmetic number, because the mean of its divisors is an integer number (3687528).

Almost surely, 2^21912117 is an apocalyptic number.

It is an amenable number.

21912117 is a deficient number, since it is larger than the sum of its proper divisors (7588107).

21912117 is a wasteful number, since it uses less digits than its factorization.

21912117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71019.

The product of its digits is 252, while the sum is 24.

The square root of 21912117 is about 4681.0380259084. The cubic root of 21912117 is about 279.8303266245.

The spelling of 21912117 in words is "twenty-one million, nine hundred twelve thousand, one hundred seventeen".