1234557777781 has 4 divisors (see below), whose sum is σ = 1257851320812. Its totient is φ = 1211264234752.

The previous prime is 1234557777779. The next prime is 1234557777839. The reversal of 1234557777781 is 1877777554321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 521320100625 + 713237677156 = 722025^2 + 844534^2 .

It is a cyclic number.

It is not a de Polignac number, because 1234557777781 - 2¹ = 1234557777779 is a prime.

It is a super-2 number, since 2×1234557777781² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1234557777701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11646771436 + ... + 11646771541.

It is an arithmetic number, because the mean of its divisors is an integer number (314462830203).

Almost surely, 2^{1234557777781} is an apocalyptic number.

It is an amenable number.

1234557777781 is a deficient number, since it is larger than the sum of its proper divisors (23293543031).

1234557777781 is an equidigital number, since it uses as much as digits as its factorization.

1234557777781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23293543030.

The product of its digits is 80673600, while the sum is 64.

The spelling of 1234557777781 in words is "one trillion, two hundred thirty-four billion, five hundred fifty-seven million, seven hundred seventy-seven thousand, seven hundred eighty-one".