1155221439991 has 2 divisors, whose sum is σ = 1155221439992. Its totient is φ = 1155221439990.

The previous prime is 1155221439947. The next prime is 1155221440007. The reversal of 1155221439991 is 1999341225511.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1155221439991 - 2¹⁷ = 1155221308919 is a prime.

It is a super-2 number, since 2×1155221439991² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1155221439941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 577610719995 + 577610719996.

It is an arithmetic number, because the mean of its divisors is an integer number (577610719996).

Almost surely, 2^{1155221439991} is an apocalyptic number.

1155221439991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1155221439991 is an equidigital number, since it uses as much as digits as its factorization.

1155221439991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 874800, while the sum is 52.

The spelling of 1155221439991 in words is "one trillion, one hundred fifty-five billion, two hundred twenty-one million, four hundred thirty-nine thousand, nine hundred ninety-one".