21165351242 has 32 divisors (see below), whose sum is σ = 37545811200. Its totient is φ = 8755463808.

The previous prime is 21165351191. The next prime is 21165351289. The reversal of 21165351242 is 24215356112.

It is a junction number, because it is equal to n+sod(n) for n = 21165351199 and 21165351208.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1979603 + ... + 1990265.

It is an arithmetic number, because the mean of its divisors is an integer number (1173306600).

Almost surely, 2^21165351242 is an apocalyptic number.

21165351242 is a deficient number, since it is larger than the sum of its proper divisors (16380459958).

21165351242 is a wasteful number, since it uses less digits than its factorization.

21165351242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15590.

The product of its digits is 14400, while the sum is 32.

The spelling of 21165351242 in words is "twenty-one billion, one hundred sixty-five million, three hundred fifty-one thousand, two hundred forty-two".