1918139064438 has 64 divisors (see below), whose sum is σ = 4091025945600. Its totient is φ = 597808823040.

The previous prime is 1918139064409. The next prime is 1918139064449. The reversal of 1918139064438 is 8344609318191.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21940020 + ... + 22027272.

It is an arithmetic number, because the mean of its divisors is an integer number (63922280400).

Almost surely, 2^{1918139064438} is an apocalyptic number.

1918139064438 is an abundant number, since it is smaller than the sum of its proper divisors (2172886881162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1918139064438 is a wasteful number, since it uses less digits than its factorization.

1918139064438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89797.

The product of its (nonzero) digits is 4478976, while the sum is 57.

The spelling of 1918139064438 in words is "one trillion, nine hundred eighteen billion, one hundred thirty-nine million, sixty-four thousand, four hundred thirty-eight".