2555581781 has 2 divisors, whose sum is σ = 2555581782. Its totient is φ = 2555581780.

The previous prime is 2555581759. The next prime is 2555581789. The reversal of 2555581781 is 1871855552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2521546225 + 34035556 = 50215^2 + 5834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2555581781 is a prime.

It is a super-2 number, since 2×2555581781² = 13061996478758263922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2555581789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1277790890 + 1277790891.

It is an arithmetic number, because the mean of its divisors is an integer number (1277790891).

Almost surely, 2^2555581781 is an apocalyptic number.

It is an amenable number.

2555581781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2555581781 is an equidigital number, since it uses as much as digits as its factorization.

2555581781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 560000, while the sum is 47.

The square root of 2555581781 is about 50552.7623478678. The cubic root of 2555581781 is about 1367.1933199742.

The spelling of 2555581781 in words is "two billion, five hundred fifty-five million, five hundred eighty-one thousand, seven hundred eighty-one".