1171200991 has 8 divisors (see below), whose sum is σ = 1186644800. Its totient is φ = 1155772800.

The previous prime is 1171200857. The next prime is 1171201001. The reversal of 1171200991 is 1990021711.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1171200991 is a prime.

It is a super-2 number, since 2×1171200991² = 2743423522638764162, 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 (1171200791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 276691 + ... + 280891.

It is an arithmetic number, because the mean of its divisors is an integer number (148330600).

Almost surely, 2^1171200991 is an apocalyptic number.

1171200991 is a deficient number, since it is larger than the sum of its proper divisors (15443809).

1171200991 is an equidigital number, since it uses as much as digits as its factorization.

1171200991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7809.

The product of its (nonzero) digits is 1134, while the sum is 31.

The square root of 1171200991 is about 34222.8138965807. The cubic root of 1171200991 is about 1054.0886662120.

The spelling of 1171200991 in words is "one billion, one hundred seventy-one million, two hundred thousand, nine hundred ninety-one".