161111491 has 2 divisors, whose sum is σ = 161111492. Its totient is φ = 161111490.

The previous prime is 161111473. The next prime is 161111513. The reversal of 161111491 is 194111161.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161111491 is a prime.

It is not a weakly prime, because it can be changed into another prime (161111191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80555745 + 80555746.

It is an arithmetic number, because the mean of its divisors is an integer number (80555746).

Almost surely, 2^161111491 is an apocalyptic number.

161111491 is a deficient number, since it is larger than the sum of its proper divisors (1).

161111491 is an equidigital number, since it uses as much as digits as its factorization.

161111491 is an odious number, because the sum of its binary digits is odd.

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

The square root of 161111491 is about 12692.9701409875. The cubic root of 161111491 is about 544.1377280222.

The spelling of 161111491 in words is "one hundred sixty-one million, one hundred eleven thousand, four hundred ninety-one".