161121899 has 2 divisors, whose sum is σ = 161121900. Its totient is φ = 161121898.

The previous prime is 161121871. The next prime is 161121901. The reversal of 161121899 is 998121161.

161121899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (998121161) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161121899 is a prime.

It is a Sophie Germain prime.

Together with 161121901, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161121599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80560949 + 80560950.

It is an arithmetic number, because the mean of its divisors is an integer number (80560950).

Almost surely, 2^161121899 is an apocalyptic number.

161121899 is a deficient number, since it is larger than the sum of its proper divisors (1).

161121899 is an equidigital number, since it uses as much as digits as its factorization.

161121899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 38.

The square root of 161121899 is about 12693.3801250888. The cubic root of 161121899 is about 544.1494450916.

The spelling of 161121899 in words is "one hundred sixty-one million, one hundred twenty-one thousand, eight hundred ninety-nine".