1318778681 has 4 divisors (see below), whose sum is σ = 1438667664. Its totient is φ = 1198889700.

The previous prime is 1318778677. The next prime is 1318778693. The reversal of 1318778681 is 1868778131.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1318778681 - 2² = 1318778677 is a prime.

It is a super-2 number, since 2×1318778681² = 3478354418920199522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1318778641) 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 in 3 ways as a sum of consecutive naturals, for example, 59944475 + ... + 59944496.

It is an arithmetic number, because the mean of its divisors is an integer number (359666916).

Almost surely, 2^1318778681 is an apocalyptic number.

1318778681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1318778681 is a deficient number, since it is larger than the sum of its proper divisors (119888983).

1318778681 is a wasteful number, since it uses less digits than its factorization.

1318778681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119888982.

The product of its digits is 451584, while the sum is 50.

The square root of 1318778681 is about 36314.9925099813. The cubic root of 1318778681 is about 1096.6228879871.

The spelling of 1318778681 in words is "one billion, three hundred eighteen million, seven hundred seventy-eight thousand, six hundred eighty-one".