18500022217 has 4 divisors (see below), whose sum is σ = 19588258836. Its totient is φ = 17411785600.

The previous prime is 18500022209. The next prime is 18500022257. The reversal of 18500022217 is 71222000581.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7111717561 + 11388304656 = 84331^2 + 106716^2 .

It is a cyclic number.

It is not a de Polignac number, because 18500022217 - 2³ = 18500022209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18500022257) 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, 544118284 + ... + 544118317.

It is an arithmetic number, because the mean of its divisors is an integer number (4897064709).

Almost surely, 2^18500022217 is an apocalyptic number.

18500022217 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18500022217 is a deficient number, since it is larger than the sum of its proper divisors (1088236619).

18500022217 is a wasteful number, since it uses less digits than its factorization.

18500022217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1088236618.

The product of its (nonzero) digits is 2240, while the sum is 28.

Adding to 18500022217 its reverse (71222000581), we get a palindrome (89722022798).

The spelling of 18500022217 in words is "eighteen billion, five hundred million, twenty-two thousand, two hundred seventeen".