1111215991 has 2 divisors, whose sum is σ = 1111215992. Its totient is φ = 1111215990.

The previous prime is 1111215961. The next prime is 1111216061. The reversal of 1111215991 is 1995121111.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1111215991 is a prime.

It is a super-2 number, since 2×1111215991² = 2469601957308224162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1111215961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 555607995 + 555607996.

It is an arithmetic number, because the mean of its divisors is an integer number (555607996).

Almost surely, 2^1111215991 is an apocalyptic number.

1111215991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1111215991 is an equidigital number, since it uses as much as digits as its factorization.

1111215991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 810, while the sum is 31.

The square root of 1111215991 is about 33334.9064945441. The cubic root of 1111215991 is about 1035.7767562460.

The spelling of 1111215991 in words is "one billion, one hundred eleven million, two hundred fifteen thousand, nine hundred ninety-one".