1081173991 has 2 divisors, whose sum is σ = 1081173992. Its totient is φ = 1081173990.

The previous prime is 1081173979. The next prime is 1081174001. The reversal of 1081173991 is 1993711801.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1081173991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1081173901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540586995 + 540586996.

It is an arithmetic number, because the mean of its divisors is an integer number (540586996).

Almost surely, 2^1081173991 is an apocalyptic number.

1081173991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081173991 is an equidigital number, since it uses as much as digits as its factorization.

1081173991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608, while the sum is 40.

The square root of 1081173991 is about 32881.2103031503. The cubic root of 1081173991 is about 1026.3571919706.

The spelling of 1081173991 in words is "one billion, eighty-one million, one hundred seventy-three thousand, nine hundred ninety-one".