161869657 has 4 divisors (see below), whose sum is σ = 163918720. Its totient is φ = 159820596.

The previous prime is 161869637. The next prime is 161869703. The reversal of 161869657 is 756968161.

It is a happy number.

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: 756968161 = 19661 ⋅38501.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161869657 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161869657.

It is not an unprimeable number, because it can be changed into a prime (161869637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1024413 + ... + 1024570.

It is an arithmetic number, because the mean of its divisors is an integer number (40979680).

Almost surely, 2^161869657 is an apocalyptic number.

It is an amenable number.

161869657 is a deficient number, since it is larger than the sum of its proper divisors (2049063).

161869657 is an equidigital number, since it uses as much as digits as its factorization.

161869657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049062.

The product of its digits is 544320, while the sum is 49.

The square root of 161869657 is about 12722.8006743798. The cubic root of 161869657 is about 544.9899355659.

The spelling of 161869657 in words is "one hundred sixty-one million, eight hundred sixty-nine thousand, six hundred fifty-seven".