1171023991 has 2 divisors, whose sum is σ = 1171023992. Its totient is φ = 1171023990.

The previous prime is 1171023961. The next prime is 1171024003. The reversal of 1171023991 is 1993201711.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1171023991 - 2²¹ = 1168926839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1171023901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 585511995 + 585511996.

It is an arithmetic number, because the mean of its divisors is an integer number (585511996).

Almost surely, 2^1171023991 is an apocalyptic number.

1171023991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1171023991 is an equidigital number, since it uses as much as digits as its factorization.

1171023991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 34.

The square root of 1171023991 is about 34220.2278046187. The cubic root of 1171023991 is about 1054.0355631451.

The spelling of 1171023991 in words is "one billion, one hundred seventy-one million, twenty-three thousand, nine hundred ninety-one".