1387778777831 has 4 divisors (see below), whose sum is σ = 1389452818200. Its totient is φ = 1386104737464.

The previous prime is 1387778777809. The next prime is 1387778777851.

1387778777831 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is not a de Polignac number, because 1387778777831 - 2³⁴ = 1370598908647 is a prime.

It is a super-2 number, since 2×1387778777831² (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 (1387778777851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 837018941 + ... + 837020598.

It is an arithmetic number, because the mean of its divisors is an integer number (347363204550).

Almost surely, 2^{1387778777831} is an apocalyptic number.

1387778777831 is a deficient number, since it is larger than the sum of its proper divisors (1674040369).

1387778777831 is an equidigital number, since it uses as much as digits as its factorization.

1387778777831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1674040368.

The product of its digits is 542126592, while the sum is 74.

The spelling of 1387778777831 in words is "one trillion, three hundred eighty-seven billion, seven hundred seventy-eight million, seven hundred seventy-seven thousand, eight hundred thirty-one".