2540204399981 has 2 divisors, whose sum is σ = 2540204399982. Its totient is φ = 2540204399980.

The previous prime is 2540204399951. The next prime is 2540204400079. The reversal of 2540204399981 is 1899934020452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1648566121225 + 891638278756 = 1283965^2 + 944266^2 .

It is a cyclic number.

It is not a de Polignac number, because 2540204399981 - 2³⁴ = 2523024530797 is a prime.

It is a super-2 number, since 2×2540204399981² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2540204399911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1270102199990 + 1270102199991.

It is an arithmetic number, because the mean of its divisors is an integer number (1270102199991).

Almost surely, 2^{2540204399981} is an apocalyptic number.

It is an amenable number.

2540204399981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2540204399981 is an equidigital number, since it uses as much as digits as its factorization.

2540204399981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5598720, while the sum is 56.

The spelling of 2540204399981 in words is "two trillion, five hundred forty billion, two hundred four million, three hundred ninety-nine thousand, nine hundred eighty-one".