1684742638 has 4 divisors (see below), whose sum is σ = 2527113960. Its totient is φ = 842371318.

The previous prime is 1684742629. The next prime is 1684742693. The reversal of 1684742638 is 8362474861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8362474861 = 13 ⋅643267297.

It is a junction number, because it is equal to n+sod(n) for n = 1684742591 and 1684742600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 421185658 + ... + 421185661.

It is an arithmetic number, because the mean of its divisors is an integer number (631778490).

Almost surely, 2^1684742638 is an apocalyptic number.

1684742638 is a deficient number, since it is larger than the sum of its proper divisors (842371322).

1684742638 is an equidigital number, since it uses as much as digits as its factorization.

1684742638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842371321.

The product of its digits is 1548288, while the sum is 49.

The square root of 1684742638 is about 41045.6165503699. The cubic root of 1684742638 is about 1189.9019851951.

The spelling of 1684742638 in words is "one billion, six hundred eighty-four million, seven hundred forty-two thousand, six hundred thirty-eight".