18220291 has 2 divisors, whose sum is σ = 18220292. Its totient is φ = 18220290.

The previous prime is 18220283. The next prime is 18220313. The reversal of 18220291 is 19202281.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18220291 - 2³ = 18220283 is a prime.

It is not a weakly prime, because it can be changed into another prime (18220271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9110145 + 9110146.

It is an arithmetic number, because the mean of its divisors is an integer number (9110146).

Almost surely, 2^18220291 is an apocalyptic number.

18220291 is a deficient number, since it is larger than the sum of its proper divisors (1).

18220291 is an equidigital number, since it uses as much as digits as its factorization.

18220291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 18220291 is about 4268.5232809486. The cubic root of 18220291 is about 263.1389291378.

The spelling of 18220291 in words is "eighteen million, two hundred twenty thousand, two hundred ninety-one".