1638111398 has 64 divisors (see below), whose sum is σ = 3312949248. Its totient is φ = 587857920.

The previous prime is 1638111389. The next prime is 1638111403. The reversal of 1638111398 is 8931118361.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 116390 + ... + 129702.

It is an arithmetic number, because the mean of its divisors is an integer number (51764832).

Almost surely, 2^1638111398 is an apocalyptic number.

1638111398 is an abundant number, since it is smaller than the sum of its proper divisors (1674837850).

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

1638111398 is a wasteful number, since it uses less digits than its factorization.

1638111398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13397.

The product of its digits is 31104, while the sum is 41.

The square root of 1638111398 is about 40473.5888944877. The cubic root of 1638111398 is about 1178.8208555224.

The spelling of 1638111398 in words is "one billion, six hundred thirty-eight million, one hundred eleven thousand, three hundred ninety-eight".