2061981 has 12 divisors (see below), whose sum is σ = 3153852. Its totient is φ = 1293696.

The previous prime is 2061971. The next prime is 2062001. The reversal of 2061981 is 1891602.

It can be written as a sum of positive squares in 2 ways, for example, as 1512900 + 549081 = 1230^2 + 741^2 .

It is not a de Polignac number, because 2061981 - 2¹¹ = 2059933 is a prime.

It is a super-2 number, since 2×2061981² = 8503531288722, which contains 22 as substring.

It is an Ulam number.

It is a Curzon number.

2061981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2061971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6586 + ... + 6891.

It is an arithmetic number, because the mean of its divisors is an integer number (262821).

2^2061981 is an apocalyptic number.

It is an amenable number.

2061981 is a deficient number, since it is larger than the sum of its proper divisors (1091871).

2061981 is a wasteful number, since it uses less digits than its factorization.

2061981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13500 (or 13497 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 2061981 is about 1435.9599576590. The cubic root of 2061981 is about 127.2804063239.

It can be divided in two parts, 206 and 1981, that added together give a 7-th power (2187 = 3⁷).

The spelling of 2061981 in words is "two million, sixty-one thousand, nine hundred eighty-one".