1181191961 has 2 divisors, whose sum is σ = 1181191962. Its totient is φ = 1181191960.

The previous prime is 1181191937. The next prime is 1181191969. The reversal of 1181191961 is 1691911811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1107558400 + 73633561 = 33280^2 + 8581^2 .

It is an emirp because it is prime and its reverse (1691911811) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1961611811 and 1181161691.

It is a cyclic number.

It is not a de Polignac number, because 1181191961 - 2¹⁸ = 1180929817 is a prime.

It is not a weakly prime, because it can be changed into another prime (1181191969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 590595980 + 590595981.

It is an arithmetic number, because the mean of its divisors is an integer number (590595981).

Almost surely, 2^1181191961 is an apocalyptic number.

It is an amenable number.

1181191961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1181191961 is an equidigital number, since it uses as much as digits as its factorization.

1181191961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 38.

The square root of 1181191961 is about 34368.4733585884. The cubic root of 1181191961 is about 1057.0774965877.

The spelling of 1181191961 in words is "one billion, one hundred eighty-one million, one hundred ninety-one thousand, nine hundred sixty-one".