20918105 has 8 divisors (see below), whose sum is σ = 27032712. Its totient is φ = 15447168.

The previous prime is 20918099. The next prime is 20918113. The reversal of 20918105 is 50181902.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3345241 + 17572864 = 1829^2 + 4192^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20918105 - 2⁸ = 20917849 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160844 + ... + 160973.

It is an arithmetic number, because the mean of its divisors is an integer number (3379089).

Almost surely, 2^20918105 is an apocalyptic number.

It is an amenable number.

20918105 is a deficient number, since it is larger than the sum of its proper divisors (6114607).

20918105 is a wasteful number, since it uses less digits than its factorization.

20918105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321835.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 20918105 is about 4573.6314893091. The cubic root of 20918105 is about 275.5333121775.

The spelling of 20918105 in words is "twenty million, nine hundred eighteen thousand, one hundred five".