20918673 has 24 divisors (see below), whose sum is σ = 31039008. Its totient is φ = 13571712.

The previous prime is 20918629. The next prime is 20918699. The reversal of 20918673 is 37681902.

It is not a de Polignac number, because 20918673 - 2¹³ = 20910481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20918603) 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 23 ways as a sum of consecutive naturals, for example, 67986 + ... + 68292.

It is an arithmetic number, because the mean of its divisors is an integer number (1293292).

Almost surely, 2^20918673 is an apocalyptic number.

It is an amenable number.

20918673 is a deficient number, since it is larger than the sum of its proper divisors (10120335).

20918673 is a wasteful number, since it uses less digits than its factorization.

20918673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 20918673 is about 4573.6935839647. The cubic root of 20918673 is about 275.5358060539.

The spelling of 20918673 in words is "twenty million, nine hundred eighteen thousand, six hundred seventy-three".