2531981 has 2 divisors, whose sum is σ = 2531982. Its totient is φ = 2531980.

The previous prime is 2531951. The next prime is 2531983. The reversal of 2531981 is 1891352.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2464900 + 67081 = 1570^2 + 259^2 .

It is a cyclic number.

It is not a de Polignac number, because 2531981 - 2⁶ = 2531917 is a prime.

It is a super-2 number, since 2×2531981² = 12821855568722, which contains 22 as substring.

Together with 2531983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2531983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1265990 + 1265991.

It is an arithmetic number, because the mean of its divisors is an integer number (1265991).

2^2531981 is an apocalyptic number.

It is an amenable number.

2531981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2531981 is an equidigital number, since it uses as much as digits as its factorization.

2531981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 29.

The square root of 2531981 is about 1591.2199722226. The cubic root of 2531981 is about 136.2971623617.

The spelling of 2531981 in words is "two million, five hundred thirty-one thousand, nine hundred eighty-one".