56261367781 has 2 divisors, whose sum is σ = 56261367782. Its totient is φ = 56261367780.

The previous prime is 56261367763. The next prime is 56261367793. The reversal of 56261367781 is 18776316265.

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., 29150098756 + 27111269025 = 170734^2 + 164655^2 .

It is a cyclic number.

It is not a de Polignac number, because 56261367781 - 2¹⁷ = 56261236709 is a prime.

It is a super-2 number, since 2×56261367781² (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 (56261367181) 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, 28130683890 + 28130683891.

It is an arithmetic number, because the mean of its divisors is an integer number (28130683891).

Almost surely, 2^56261367781 is an apocalyptic number.

It is an amenable number.

56261367781 is a deficient number, since it is larger than the sum of its proper divisors (1).

56261367781 is an equidigital number, since it uses as much as digits as its factorization.

56261367781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 52.

The spelling of 56261367781 in words is "fifty-six billion, two hundred sixty-one million, three hundred sixty-seven thousand, seven hundred eighty-one".