1071195991 has 4 divisors (see below), whose sum is σ = 1100147272. Its totient is φ = 1042244712.

The previous prime is 1071195977. The next prime is 1071196033. The reversal of 1071195991 is 1995911701.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1995911701 = 7 ⋅285130243.

It is a de Polignac number, because none of the positive numbers 2^k-1071195991 is a prime.

It is a super-2 number, since 2×1071195991² = 2294921702268944162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1071195691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14475585 + ... + 14475658.

It is an arithmetic number, because the mean of its divisors is an integer number (275036818).

Almost surely, 2^1071195991 is an apocalyptic number.

1071195991 is a deficient number, since it is larger than the sum of its proper divisors (28951281).

1071195991 is an equidigital number, since it uses as much as digits as its factorization.

1071195991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28951280.

The product of its (nonzero) digits is 25515, while the sum is 43.

The square root of 1071195991 is about 32729.1306178456. The cubic root of 1071195991 is about 1023.1900610275.

The spelling of 1071195991 in words is "one billion, seventy-one million, one hundred ninety-five thousand, nine hundred ninety-one".