161817949 has 4 divisors (see below), whose sum is σ = 168853536. Its totient is φ = 154782364.

The previous prime is 161817947. The next prime is 161817973. The reversal of 161817949 is 949718161.

161817949 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 949718161 = 7 ⋅135674023.

It is not a de Polignac number, because 161817949 - 2¹ = 161817947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 161817899 and 161817908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161817947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3517759 + ... + 3517804.

It is an arithmetic number, because the mean of its divisors is an integer number (42213384).

Almost surely, 2^161817949 is an apocalyptic number.

It is an amenable number.

161817949 is a deficient number, since it is larger than the sum of its proper divisors (7035587).

161817949 is an equidigital number, since it uses as much as digits as its factorization.

161817949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7035586.

The product of its digits is 108864, while the sum is 46.

The square root of 161817949 is about 12720.7684123248. The cubic root of 161817949 is about 544.9318984569.

The spelling of 161817949 in words is "one hundred sixty-one million, eight hundred seventeen thousand, nine hundred forty-nine".