31730161 has 4 divisors (see below), whose sum is σ = 31851072. Its totient is φ = 31609252.

The previous prime is 31730137. The next prime is 31730197. The reversal of 31730161 is 16103713.

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.

It is a cyclic number.

It is not a de Polignac number, because 31730161 - 2²³ = 23341553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31730561) 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, 60061 + ... + 60586.

It is an arithmetic number, because the mean of its divisors is an integer number (7962768).

Almost surely, 2^31730161 is an apocalyptic number.

It is an amenable number.

31730161 is a deficient number, since it is larger than the sum of its proper divisors (120911).

31730161 is a wasteful number, since it uses less digits than its factorization.

31730161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120910.

The product of its (nonzero) digits is 378, while the sum is 22.

The square root of 31730161 is about 5632.9531331265. The cubic root of 31730161 is about 316.5853096015.

Adding to 31730161 its reverse (16103713), we get a palindrome (47833874).

The spelling of 31730161 in words is "thirty-one million, seven hundred thirty thousand, one hundred sixty-one".