160831721 has 2 divisors, whose sum is σ = 160831722. Its totient is φ = 160831720.

The previous prime is 160831703. The next prime is 160831753. The reversal of 160831721 is 127138061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131790400 + 29041321 = 11480^2 + 5389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-160831721 is a prime.

It is not a weakly prime, because it can be changed into another prime (160831771) 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 as a sum of consecutive naturals, namely, 80415860 + 80415861.

It is an arithmetic number, because the mean of its divisors is an integer number (80415861).

Almost surely, 2^160831721 is an apocalyptic number.

It is an amenable number.

160831721 is a deficient number, since it is larger than the sum of its proper divisors (1).

160831721 is an equidigital number, since it uses as much as digits as its factorization.

160831721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 160831721 is about 12681.9446852602. The cubic root of 160831721 is about 543.8225805963.

Adding to 160831721 its reverse (127138061), we get a palindrome (287969782).

The spelling of 160831721 in words is "one hundred sixty million, eight hundred thirty-one thousand, seven hundred twenty-one".