21212715238 has 32 divisors (see below), whose sum is σ = 37483891200. Its totient is φ = 8876144160.

The previous prime is 21212715233. The next prime is 21212715263. The reversal of 21212715238 is 83251721212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212715233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3913 + ... + 206011.

It is an arithmetic number, because the mean of its divisors is an integer number (1171371600).

Almost surely, 2^21212715238 is an apocalyptic number.

21212715238 is a deficient number, since it is larger than the sum of its proper divisors (16271175962).

21212715238 is a wasteful number, since it uses less digits than its factorization.

21212715238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202492.

The product of its digits is 13440, while the sum is 34.

The spelling of 21212715238 in words is "twenty-one billion, two hundred twelve million, seven hundred fifteen thousand, two hundred thirty-eight".