220545991 has 2 divisors, whose sum is σ = 220545992. Its totient is φ = 220545990.

The previous prime is 220545989. The next prime is 220546019. The reversal of 220545991 is 199545022.

220545991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 220545991 - 2¹ = 220545989 is a prime.

Together with 220545989, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 220545991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220545931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110272995 + 110272996.

It is an arithmetic number, because the mean of its divisors is an integer number (110272996).

Almost surely, 2^220545991 is an apocalyptic number.

220545991 is a deficient number, since it is larger than the sum of its proper divisors (1).

220545991 is an equidigital number, since it uses as much as digits as its factorization.

220545991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 220545991 is about 14850.7909216984. The cubic root of 220545991 is about 604.1800617709.

The spelling of 220545991 in words is "two hundred twenty million, five hundred forty-five thousand, nine hundred ninety-one".