18387831050391 has 48 divisors (see below), whose sum is σ = 27441517872384. Its totient is φ = 10941586656000.

The previous prime is 18387831050383. The next prime is 18387831050399. The reversal of 18387831050391 is 19305013878381.

It is an interprime number because it is at equal distance from previous prime (18387831050383) and next prime (18387831050399).

It is not a de Polignac number, because 18387831050391 - 2³ = 18387831050383 is a prime.

It is a super-2 number, since 2×18387831050391² (a number of 27 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18387831050399) 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 47 ways as a sum of consecutive naturals, for example, 4731100 + ... + 7691486.

It is an arithmetic number, because the mean of its divisors is an integer number (571698289008).

Almost surely, 2^{18387831050391} is an apocalyptic number.

18387831050391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18387831050391 is a deficient number, since it is larger than the sum of its proper divisors (9053686821993).

18387831050391 is a wasteful number, since it uses less digits than its factorization.

18387831050391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2960724 (or 2960713 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 57.

The spelling of 18387831050391 in words is "eighteen trillion, three hundred eighty-seven billion, eight hundred thirty-one million, fifty thousand, three hundred ninety-one".