21920117 has 4 divisors (see below), whose sum is σ = 22454796. Its totient is φ = 21385440.

The previous prime is 21920113. The next prime is 21920141. The reversal of 21920117 is 71102912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2436721 + 19483396 = 1561^2 + 4414^2 .

It is a cyclic number.

It is not a de Polignac number, because 21920117 - 2² = 21920113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21920092 and 21920101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21920113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267278 + ... + 267359.

It is an arithmetic number, because the mean of its divisors is an integer number (5613699).

Almost surely, 2^21920117 is an apocalyptic number.

It is an amenable number.

21920117 is a deficient number, since it is larger than the sum of its proper divisors (534679).

21920117 is an equidigital number, since it uses as much as digits as its factorization.

21920117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534678.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 21920117 is about 4681.8924592519. The cubic root of 21920117 is about 279.8643773467.

The spelling of 21920117 in words is "twenty-one million, nine hundred twenty thousand, one hundred seventeen".