161893009 has 2 divisors, whose sum is σ = 161893010. Its totient is φ = 161893008.

The previous prime is 161893007. The next prime is 161893087. The reversal of 161893009 is 900398161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132894784 + 28998225 = 11528^2 + 5385^2 .

It is a cyclic number.

It is not a de Polignac number, because 161893009 - 2¹ = 161893007 is a prime.

Together with 161893007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (161893003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80946504 + 80946505.

It is an arithmetic number, because the mean of its divisors is an integer number (80946505).

Almost surely, 2^161893009 is an apocalyptic number.

It is an amenable number.

161893009 is a deficient number, since it is larger than the sum of its proper divisors (1).

161893009 is an equidigital number, since it uses as much as digits as its factorization.

161893009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 161893009 is about 12723.7183637489. The cubic root of 161893009 is about 545.0161418219.

The spelling of 161893009 in words is "one hundred sixty-one million, eight hundred ninety-three thousand, nine".