20215218 has 8 divisors (see below), whose sum is σ = 40430448. Its totient is φ = 6738404.

The previous prime is 20215211. The next prime is 20215241. The reversal of 20215218 is 81251202.

It is a happy number.

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

20215218 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 20215194 and 20215203.

It is not an unprimeable number, because it can be changed into a prime (20215211) 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 3 ways as a sum of consecutive naturals, for example, 1684596 + ... + 1684607.

It is an arithmetic number, because the mean of its divisors is an integer number (5053806).

Almost surely, 2^20215218 is an apocalyptic number.

20215218 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20215218 is a wasteful number, since it uses less digits than its factorization.

20215218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3369208.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 20215218 is about 4496.1336723901. The cubic root of 20215218 is about 272.4119424815.

The spelling of 20215218 in words is "twenty million, two hundred fifteen thousand, two hundred eighteen".