2556183781 has 2 divisors, whose sum is σ = 2556183782. Its totient is φ = 2556183780.

The previous prime is 2556183779. The next prime is 2556183793. The reversal of 2556183781 is 1873816552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2293452100 + 262731681 = 47890^2 + 16209^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556183781 - 2¹ = 2556183779 is a prime.

It is a super-2 number, since 2×2556183781² = 13068151044494911922, which contains 22 as substring.

Together with 2556183779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2556183281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1278091890 + 1278091891.

It is an arithmetic number, because the mean of its divisors is an integer number (1278091891).

Almost surely, 2^2556183781 is an apocalyptic number.

It is an amenable number.

2556183781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2556183781 is an equidigital number, since it uses as much as digits as its factorization.

2556183781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 403200, while the sum is 46.

The square root of 2556183781 is about 50558.7161723871. The cubic root of 2556183781 is about 1367.3006648413.

The spelling of 2556183781 in words is "two billion, five hundred fifty-six million, one hundred eighty-three thousand, seven hundred eighty-one".