161039869 has 2 divisors, whose sum is σ = 161039870. Its totient is φ = 161039868.

The previous prime is 161039867. The next prime is 161039891. The reversal of 161039869 is 968930161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132020100 + 29019769 = 11490^2 + 5387^2 .

It is a cyclic number.

It is not a de Polignac number, because 161039869 - 2¹ = 161039867 is a prime.

It is a super-2 number, since 2×161039869² = 51867678815074322, which contains 22 as substring.

Together with 161039867, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161039867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80519934 + 80519935.

It is an arithmetic number, because the mean of its divisors is an integer number (80519935).

Almost surely, 2^161039869 is an apocalyptic number.

It is an amenable number.

161039869 is a deficient number, since it is larger than the sum of its proper divisors (1).

161039869 is an equidigital number, since it uses as much as digits as its factorization.

161039869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 161039869 is about 12690.1485018892. The cubic root of 161039869 is about 544.0570840562.

The spelling of 161039869 in words is "one hundred sixty-one million, thirty-nine thousand, eight hundred sixty-nine".