2520811981 has 2 divisors, whose sum is σ = 2520811982. Its totient is φ = 2520811980.

The previous prime is 2520811973. The next prime is 2520811987. The reversal of 2520811981 is 1891180252.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2140912900 + 379899081 = 46270^2 + 19491^2 .

It is a cyclic number.

It is not a de Polignac number, because 2520811981 - 2³ = 2520811973 is a prime.

It is a super-2 number, since 2×2520811981² = 12708986087106288722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2520811981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2520811987) 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 as a sum of consecutive naturals, namely, 1260405990 + 1260405991.

It is an arithmetic number, because the mean of its divisors is an integer number (1260405991).

Almost surely, 2^2520811981 is an apocalyptic number.

It is an amenable number.

2520811981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2520811981 is an equidigital number, since it uses as much as digits as its factorization.

2520811981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 37.

The square root of 2520811981 is about 50207.6884650150. The cubic root of 2520811981 is about 1360.9645660541.

The spelling of 2520811981 in words is "two billion, five hundred twenty million, eight hundred eleven thousand, nine hundred eighty-one".