161311005 has 12 divisors (see below), whose sum is σ = 279605820. Its totient is φ = 86032512.

The previous prime is 161310991. The next prime is 161311013. The reversal of 161311005 is 500113161.

It can be written as a sum of positive squares in 2 ways, for example, as 73307844 + 88003161 = 8562^2 + 9381^2 .

It is not a de Polignac number, because 161311005 - 2⁹ = 161310493 is a prime.

It is a super-2 number, since 2×161311005² = 52042480668220050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1792300 + ... + 1792389.

It is an arithmetic number, because the mean of its divisors is an integer number (23300485).

Almost surely, 2^161311005 is an apocalyptic number.

161311005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161311005 is a deficient number, since it is larger than the sum of its proper divisors (118294815).

161311005 is a wasteful number, since it uses less digits than its factorization.

161311005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3584700 (or 3584697 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 161311005 is about 12700.8269415814. The cubic root of 161311005 is about 544.3622481385.

Adding to 161311005 its reverse (500113161), we get a palindrome (661424166).

The spelling of 161311005 in words is "one hundred sixty-one million, three hundred eleven thousand, five".