1187194391 has 2 divisors, whose sum is σ = 1187194392. Its totient is φ = 1187194390.

The previous prime is 1187194331. The next prime is 1187194433. The reversal of 1187194391 is 1934917811.

It is a strong prime.

It is an emirp because it is prime and its reverse (1934917811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1187194391 - 2¹⁰ = 1187193367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1187194331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 593597195 + 593597196.

It is an arithmetic number, because the mean of its divisors is an integer number (593597196).

Almost surely, 2^1187194391 is an apocalyptic number.

1187194391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1187194391 is an equidigital number, since it uses as much as digits as its factorization.

1187194391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 44.

The square root of 1187194391 is about 34455.6873534689. The cubic root of 1187194391 is about 1058.8650457567.

The spelling of 1187194391 in words is "one billion, one hundred eighty-seven million, one hundred ninety-four thousand, three hundred ninety-one".