20218945 has 32 divisors (see below), whose sum is σ = 27216000. Its totient is φ = 14353920.

The previous prime is 20218937. The next prime is 20218949. The reversal of 20218945 is 54981202.

It is not a de Polignac number, because 20218945 - 2³ = 20218937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20218949) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112866 + ... + 113044.

It is an arithmetic number, because the mean of its divisors is an integer number (850500).

Almost surely, 2^20218945 is an apocalyptic number.

It is an amenable number.

20218945 is a deficient number, since it is larger than the sum of its proper divisors (6997055).

20218945 is a wasteful number, since it uses less digits than its factorization.

20218945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 20218945 is about 4496.5481205031. The cubic root of 20218945 is about 272.4286826246.

The spelling of 20218945 in words is "twenty million, two hundred eighteen thousand, nine hundred forty-five".