1196777991 has 4 divisors (see below), whose sum is σ = 1595703992. Its totient is φ = 797851992.

The previous prime is 1196777977. The next prime is 1196777993. The reversal of 1196777991 is 1997776911.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1196777991 - 2¹⁰ = 1196776967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1196777993) 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, 199462996 + ... + 199463001.

It is an arithmetic number, because the mean of its divisors is an integer number (398925998).

Almost surely, 2^1196777991 is an apocalyptic number.

1196777991 is a deficient number, since it is larger than the sum of its proper divisors (398926001).

1196777991 is an equidigital number, since it uses as much as digits as its factorization.

1196777991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398926000.

The product of its digits is 1500282, while the sum is 57.

The square root of 1196777991 is about 34594.4791982767. The cubic root of 1196777991 is about 1061.7066346137.

The spelling of 1196777991 in words is "one billion, one hundred ninety-six million, seven hundred seventy-seven thousand, nine hundred ninety-one".