20161331 has 4 divisors (see below), whose sum is σ = 20308632. Its totient is φ = 20014032.

The previous prime is 20161327. The next prime is 20161343. The reversal of 20161331 is 13316102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13316102 = 2 ⋅6658051.

It is a cyclic number.

It is not a de Polignac number, because 20161331 - 2² = 20161327 is a prime.

It is a super-2 number, since 2×20161331² = 812958535383122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20161321) 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, 73445 + ... + 73718.

It is an arithmetic number, because the mean of its divisors is an integer number (5077158).

Almost surely, 2^20161331 is an apocalyptic number.

20161331 is a deficient number, since it is larger than the sum of its proper divisors (147301).

20161331 is a wasteful number, since it uses less digits than its factorization.

20161331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147300.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20161331 is about 4490.1370803128. The cubic root of 20161331 is about 272.1696740874.

Adding to 20161331 its reverse (13316102), we get a palindrome (33477433).

The spelling of 20161331 in words is "twenty million, one hundred sixty-one thousand, three hundred thirty-one".