161800731 has 24 divisors (see below), whose sum is σ = 238898400. Its totient is φ = 105494400.

The previous prime is 161800729. The next prime is 161800733. The reversal of 161800731 is 137008161.

It is an interprime number because it is at equal distance from previous prime (161800729) and next prime (161800733).

It is not a de Polignac number, because 161800731 - 2¹ = 161800729 is a prime.

It is a super-2 number, since 2×161800731² = 52358953104268722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161800695 and 161800704.

It is not an unprimeable number, because it can be changed into a prime (161800733) 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 23 ways as a sum of consecutive naturals, for example, 108511 + ... + 109991.

It is an arithmetic number, because the mean of its divisors is an integer number (9954100).

Almost surely, 2^161800731 is an apocalyptic number.

161800731 is a deficient number, since it is larger than the sum of its proper divisors (77097669).

161800731 is a wasteful number, since it uses less digits than its factorization.

161800731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1747 (or 1744 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 161800731 is about 12720.0916270285. The cubic root of 161800731 is about 544.9125702133.

Adding to 161800731 its reverse (137008161), we get a palindrome (298808892).

The spelling of 161800731 in words is "one hundred sixty-one million, eight hundred thousand, seven hundred thirty-one".