2071981 has 4 divisors (see below), whose sum is σ = 2091100. Its totient is φ = 2052864.

The previous prime is 2071973. The next prime is 2071991. The reversal of 2071981 is 1891702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1891702 = 2 ⋅945851.

It can be written as a sum of positive squares in 2 ways, for example, as 1602756 + 469225 = 1266^2 + 685^2 .

It is a cyclic number.

It is not a de Polignac number, because 2071981 - 2³ = 2071973 is a prime.

It is a super-2 number, since 2×2071981² = 8586210528722, 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 (2071921) 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, 9396 + ... + 9613.

It is an arithmetic number, because the mean of its divisors is an integer number (522775).

2^2071981 is an apocalyptic number.

It is an amenable number.

2071981 is a deficient number, since it is larger than the sum of its proper divisors (19119).

2071981 is a wasteful number, since it uses less digits than its factorization.

2071981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19118.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 2071981 is about 1439.4377374517. The cubic root of 2071981 is about 127.4858320794.

The spelling of 2071981 in words is "two million, seventy-one thousand, nine hundred eighty-one".