1311780831 has 4 divisors (see below), whose sum is σ = 1749041112. Its totient is φ = 874520552.

The previous prime is 1311780817. The next prime is 1311780839. The reversal of 1311780831 is 1380871131.

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 1311780831 - 2¹⁹ = 1311256543 is a prime.

It is a super-2 number, since 2×1311780831² = 3441537897158101122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1311780792 and 1311780801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311780839) 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, 218630136 + ... + 218630141.

It is an arithmetic number, because the mean of its divisors is an integer number (437260278).

Almost surely, 2^1311780831 is an apocalyptic number.

1311780831 is a deficient number, since it is larger than the sum of its proper divisors (437260281).

1311780831 is an equidigital number, since it uses as much as digits as its factorization.

1311780831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437260280.

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 1311780831 is about 36218.5150302991. The cubic root of 1311780831 is about 1094.6797729186.

The spelling of 1311780831 in words is "one billion, three hundred eleven million, seven hundred eighty thousand, eight hundred thirty-one".