191386638 has 40 divisors (see below), whose sum is σ = 429806520. Its totient is φ = 63653040.

The previous prime is 191386633. The next prime is 191386649. The reversal of 191386638 is 836683191.

It is a happy number.

191386638 is a `hidden beast` number, since 1 + 9 + 1 + 3 + 8 + 6 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 191386593 and 191386602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191386633) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 91468 + ... + 93536.

It is an arithmetic number, because the mean of its divisors is an integer number (10745163).

Almost surely, 2^191386638 is an apocalyptic number.

191386638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

191386638 is an abundant number, since it is smaller than the sum of its proper divisors (238419882).

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

191386638 is a wasteful number, since it uses less digits than its factorization.

191386638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2654 (or 2645 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 191386638 is about 13834.2559612001. The cubic root of 191386638 is about 576.2848525966.

The spelling of 191386638 in words is "one hundred ninety-one million, three hundred eighty-six thousand, six hundred thirty-eight".