254436778681 has 2 divisors, whose sum is σ = 254436778682. Its totient is φ = 254436778680.

The previous prime is 254436778549. The next prime is 254436778693. The reversal of 254436778681 is 186877634452.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157840138681 + 96596640000 = 397291^2 + 310800^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-254436778681 is a prime.

It is a super-2 number, since 2×254436778681² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (254436718681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127218389340 + 127218389341.

It is an arithmetic number, because the mean of its divisors is an integer number (127218389341).

Almost surely, 2^254436778681 is an apocalyptic number.

It is an amenable number.

254436778681 is a deficient number, since it is larger than the sum of its proper divisors (1).

254436778681 is an equidigital number, since it uses as much as digits as its factorization.

254436778681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54190080, while the sum is 61.

The spelling of 254436778681 in words is "two hundred fifty-four billion, four hundred thirty-six million, seven hundred seventy-eight thousand, six hundred eighty-one".