13821651638 has 36 divisors (see below), whose sum is σ = 21410486532. Its totient is φ = 6691789440.

The previous prime is 13821651629. The next prime is 13821651643. The reversal of 13821651638 is 83615612831.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 65505353 + ... + 65505563.

It is an arithmetic number, because the mean of its divisors is an integer number (594735737).

Almost surely, 2^13821651638 is an apocalyptic number.

13821651638 is a deficient number, since it is larger than the sum of its proper divisors (7588834894).

13821651638 is an frugal number, since it uses more digits than its factorization.

13821651638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525 (or 369 counting only the distinct ones).

The product of its digits is 207360, while the sum is 44.

The spelling of 13821651638 in words is "thirteen billion, eight hundred twenty-one million, six hundred fifty-one thousand, six hundred thirty-eight".