2542647781 has 2 divisors, whose sum is σ = 2542647782. Its totient is φ = 2542647780.

The previous prime is 2542647763. The next prime is 2542647797. The reversal of 2542647781 is 1877462452.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2484125281 + 58522500 = 49841^2 + 7650^2 .

It is a cyclic number.

It is not a de Polignac number, because 2542647781 - 2¹¹ = 2542645733 is a prime.

It is a super-2 number, since 2×2542647781² = 12930115476448447922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2542147781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271323890 + 1271323891.

It is an arithmetic number, because the mean of its divisors is an integer number (1271323891).

Almost surely, 2^2542647781 is an apocalyptic number.

It is an amenable number.

2542647781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2542647781 is an equidigital number, since it uses as much as digits as its factorization.

2542647781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 752640, while the sum is 46.

The square root of 2542647781 is about 50424.6743271585. The cubic root of 2542647781 is about 1364.8829269815.

The spelling of 2542647781 in words is "two billion, five hundred forty-two million, six hundred forty-seven thousand, seven hundred eighty-one".