1161111661 has 2 divisors, whose sum is σ = 1161111662. Its totient is φ = 1161111660.

The previous prime is 1161111649. The next prime is 1161111673. The reversal of 1161111661 is 1661111611.

It is a balanced prime because it is at equal distance from previous prime (1161111649) and next prime (1161111673).

It can be written as a sum of positive squares in only one way, i.e., 760711561 + 400400100 = 27581^2 + 20010^2 .

It is an emirp because it is prime and its reverse (1661111611) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1991111911 and 1191111991.

It is a cyclic number.

It is not a de Polignac number, because 1161111661 - 2¹¹ = 1161109613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1161811661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580555830 + 580555831.

It is an arithmetic number, because the mean of its divisors is an integer number (580555831).

Almost surely, 2^1161111661 is an apocalyptic number.

It is an amenable number.

1161111661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161111661 is an equidigital number, since it uses as much as digits as its factorization.

1161111661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 25.

The square root of 1161111661 is about 34075.0885692172. The cubic root of 1161111661 is about 1051.0531115174.

The spelling of 1161111661 in words is "one billion, one hundred sixty-one million, one hundred eleven thousand, six hundred sixty-one".