218055491 has 2 divisors, whose sum is σ = 218055492. Its totient is φ = 218055490.

The previous prime is 218055377. The next prime is 218055493. The reversal of 218055491 is 194550812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218055491 is a prime.

Together with 218055493, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218055493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109027745 + 109027746.

It is an arithmetic number, because the mean of its divisors is an integer number (109027746).

Almost surely, 2^218055491 is an apocalyptic number.

218055491 is a deficient number, since it is larger than the sum of its proper divisors (1).

218055491 is an equidigital number, since it uses as much as digits as its factorization.

218055491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 35.

The square root of 218055491 is about 14766.7021030425. The cubic root of 218055491 is about 601.8972269673.

The spelling of 218055491 in words is "two hundred eighteen million, fifty-five thousand, four hundred ninety-one".