1686332138 has 4 divisors (see below), whose sum is σ = 2529498210. Its totient is φ = 843166068.

The previous prime is 1686332071. The next prime is 1686332191. The reversal of 1686332138 is 8312336861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8312336861 = 37 ⋅224657753.

It can be written as a sum of positive squares in only one way, i.e., 1578234529 + 108097609 = 39727^2 + 10397^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1686332095 and 1686332104.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 421583033 + ... + 421583036.

Almost surely, 2^1686332138 is an apocalyptic number.

1686332138 is a deficient number, since it is larger than the sum of its proper divisors (843166072).

1686332138 is an equidigital number, since it uses as much as digits as its factorization.

1686332138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843166071.

The product of its digits is 124416, while the sum is 41.

The square root of 1686332138 is about 41064.9745890583. The cubic root of 1686332138 is about 1190.2760788728.

Adding to 1686332138 its reverse (8312336861), we get a palindrome (9998668999).

The spelling of 1686332138 in words is "one billion, six hundred eighty-six million, three hundred thirty-two thousand, one hundred thirty-eight".