161559947 has 4 divisors (see below), whose sum is σ = 161585376. Its totient is φ = 161534520.

The previous prime is 161559943. The next prime is 161559949. The reversal of 161559947 is 749955161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 749955161 = 6271 ⋅119591.

It is a cyclic number.

It is not a de Polignac number, because 161559947 - 2² = 161559943 is a prime.

It is a super-2 number, since 2×161559947² = 52203232949285618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161559943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5918 + ... + 18924.

It is an arithmetic number, because the mean of its divisors is an integer number (40396344).

Almost surely, 2^161559947 is an apocalyptic number.

161559947 is a deficient number, since it is larger than the sum of its proper divisors (25429).

161559947 is a wasteful number, since it uses less digits than its factorization.

161559947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25428.

The product of its digits is 340200, while the sum is 47.

The square root of 161559947 is about 12710.6233914785. The cubic root of 161559947 is about 544.6421318655.

The spelling of 161559947 in words is "one hundred sixty-one million, five hundred fifty-nine thousand, nine hundred forty-seven".