21231645338 has 16 divisors (see below), whose sum is σ = 33743666880. Its totient is φ = 9984601536.

The previous prime is 21231645319. The next prime is 21231645349. The reversal of 21231645338 is 83354613212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160118 + ... + 260961.

It is an arithmetic number, because the mean of its divisors is an integer number (2108979180).

Almost surely, 2^21231645338 is an apocalyptic number.

21231645338 is a deficient number, since it is larger than the sum of its proper divisors (12512021542).

21231645338 is a wasteful number, since it uses less digits than its factorization.

21231645338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422581.

The product of its digits is 103680, while the sum is 38.

It can be divided in two parts, 2123 and 1645338, that added together give a palindrome (1647461).

The spelling of 21231645338 in words is "twenty-one billion, two hundred thirty-one million, six hundred forty-five thousand, three hundred thirty-eight".