20501218 has 8 divisors (see below), whose sum is σ = 32560812. Its totient is φ = 9647616.

The previous prime is 20501213. The next prime is 20501227. The reversal of 20501218 is 81210502.

It can be written as a sum of positive squares in 2 ways, for example, as 18378369 + 2122849 = 4287^2 + 1457^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 20501195 and 20501204.

It is not an unprimeable number, because it can be changed into a prime (20501213) 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, 301455 + ... + 301522.

Almost surely, 2^20501218 is an apocalyptic number.

20501218 is a deficient number, since it is larger than the sum of its proper divisors (12059594).

20501218 is a wasteful number, since it uses less digits than its factorization.

20501218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602996.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 20501218 is about 4527.8270726696. The cubic root of 20501218 is about 273.6906039343.

The spelling of 20501218 in words is "twenty million, five hundred one thousand, two hundred eighteen".