3161981 has 4 divisors (see below), whose sum is σ = 3191100. Its totient is φ = 3132864.

The previous prime is 3161953. The next prime is 3161993. The reversal of 3161981 is 1891613.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1891613 = 43 ⋅43991.

It can be written as a sum of positive squares in 2 ways, for example, as 1229881 + 1932100 = 1109^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 3161981 - 2¹⁰ = 3160957 is a prime.

It is a super-2 number, since 2×3161981² = 19996247688722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3161681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14396 + ... + 14613.

It is an arithmetic number, because the mean of its divisors is an integer number (797775).

Almost surely, 2^3161981 is an apocalyptic number.

It is an amenable number.

3161981 is a deficient number, since it is larger than the sum of its proper divisors (29119).

3161981 is a wasteful number, since it uses less digits than its factorization.

3161981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29118.

The product of its digits is 1296, while the sum is 29.

The square root of 3161981 is about 1778.1959959465. The cubic root of 3161981 is about 146.7753367036.

The spelling of 3161981 in words is "three million, one hundred sixty-one thousand, nine hundred eighty-one".