220201991 has 2 divisors, whose sum is σ = 220201992. Its totient is φ = 220201990.

The previous prime is 220201987. The next prime is 220202051. The reversal of 220201991 is 199102022.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 220201991 - 2² = 220201987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 220201991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220201951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110100995 + 110100996.

It is an arithmetic number, because the mean of its divisors is an integer number (110100996).

Almost surely, 2^220201991 is an apocalyptic number.

220201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

220201991 is an equidigital number, since it uses as much as digits as its factorization.

220201991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 220201991 is about 14839.2045271975. The cubic root of 220201991 is about 603.8657719282.

The spelling of 220201991 in words is "two hundred twenty million, two hundred one thousand, nine hundred ninety-one".