25812543781 has 2 divisors, whose sum is σ = 25812543782. Its totient is φ = 25812543780.

The previous prime is 25812543751. The next prime is 25812543791. The reversal of 25812543781 is 18734521852.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15118915681 + 10693628100 = 122959^2 + 103410^2 .

It is a cyclic number.

It is not a de Polignac number, because 25812543781 - 2²⁹ = 25275672869 is a prime.

It is a super-2 number, since 2×25812543781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25812543751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12906271890 + 12906271891.

It is an arithmetic number, because the mean of its divisors is an integer number (12906271891).

Almost surely, 2^25812543781 is an apocalyptic number.

It is an amenable number.

25812543781 is a deficient number, since it is larger than the sum of its proper divisors (1).

25812543781 is an equidigital number, since it uses as much as digits as its factorization.

25812543781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 537600, while the sum is 46.

The spelling of 25812543781 in words is "twenty-five billion, eight hundred twelve million, five hundred forty-three thousand, seven hundred eighty-one".