1313011991 has 2 divisors, whose sum is σ = 1313011992. Its totient is φ = 1313011990.

The previous prime is 1313011981. The next prime is 1313011993. The reversal of 1313011991 is 1991103131.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1313011991 - 2³⁰ = 239270167 is a prime.

Together with 1313011993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1313011993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 656505995 + 656505996.

It is an arithmetic number, because the mean of its divisors is an integer number (656505996).

Almost surely, 2^1313011991 is an apocalyptic number.

1313011991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1313011991 is an equidigital number, since it uses as much as digits as its factorization.

1313011991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 1313011991 is about 36235.5073236184. The cubic root of 1313011991 is about 1095.0221330917.

The spelling of 1313011991 in words is "one billion, three hundred thirteen million, eleven thousand, nine hundred ninety-one".