1191523961 has 2 divisors, whose sum is σ = 1191523962. Its totient is φ = 1191523960.

The previous prime is 1191523903. The next prime is 1191523979. The reversal of 1191523961 is 1693251911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 802645561 + 388878400 = 28331^2 + 19720^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1191523961 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1191523561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 595761980 + 595761981.

It is an arithmetic number, because the mean of its divisors is an integer number (595761981).

Almost surely, 2^1191523961 is an apocalyptic number.

It is an amenable number.

1191523961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191523961 is an equidigital number, since it uses as much as digits as its factorization.

1191523961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14580, while the sum is 38.

The square root of 1191523961 is about 34518.4582651080. The cubic root of 1191523961 is about 1060.1506730755.

The spelling of 1191523961 in words is "one billion, one hundred ninety-one million, five hundred twenty-three thousand, nine hundred sixty-one".