1222111991 has 2 divisors, whose sum is σ = 1222111992. Its totient is φ = 1222111990.

The previous prime is 1222111951. The next prime is 1222112057. The reversal of 1222111991 is 1991112221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1222111991 - 2⁶ = 1222111927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1222111951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 611055995 + 611055996.

It is an arithmetic number, because the mean of its divisors is an integer number (611055996).

Almost surely, 2^1222111991 is an apocalyptic number.

1222111991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1222111991 is an equidigital number, since it uses as much as digits as its factorization.

1222111991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 29.

The square root of 1222111991 is about 34958.7183832588. The cubic root of 1222111991 is about 1069.1459662659.

The spelling of 1222111991 in words is "one billion, two hundred twenty-two million, one hundred eleven thousand, nine hundred ninety-one".