161813887 has 2 divisors, whose sum is σ = 161813888. Its totient is φ = 161813886.

The previous prime is 161813833. The next prime is 161813923. The reversal of 161813887 is 788318161.

It is a strong prime.

It is an emirp because it is prime and its reverse (788318161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161813887 - 2⁷ = 161813759 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161823887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80906943 + 80906944.

It is an arithmetic number, because the mean of its divisors is an integer number (80906944).

Almost surely, 2^161813887 is an apocalyptic number.

161813887 is a deficient number, since it is larger than the sum of its proper divisors (1).

161813887 is an equidigital number, since it uses as much as digits as its factorization.

161813887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 43.

The square root of 161813887 is about 12720.6087511565. The cubic root of 161813887 is about 544.9273387404.

The spelling of 161813887 in words is "one hundred sixty-one million, eight hundred thirteen thousand, eight hundred eighty-seven".