1391387811 has 32 divisors (see below), whose sum is σ = 2067690240. Its totient is φ = 825177600.

The previous prime is 1391387801. The next prime is 1391387813. The reversal of 1391387811 is 1187831931.

It is a happy number.

It is not a de Polignac number, because 1391387811 - 2⁵ = 1391387779 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1391387813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 313375 + ... + 317783.

It is an arithmetic number, because the mean of its divisors is an integer number (64615320).

Almost surely, 2^1391387811 is an apocalyptic number.

1391387811 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1391387811 is a deficient number, since it is larger than the sum of its proper divisors (676302429).

1391387811 is a wasteful number, since it uses less digits than its factorization.

1391387811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4627.

The product of its digits is 36288, while the sum is 42.

The square root of 1391387811 is about 37301.3111163669. The cubic root of 1391387811 is about 1116.3903268778.

The spelling of 1391387811 in words is "one billion, three hundred ninety-one million, three hundred eighty-seven thousand, eight hundred eleven".