21851683539 has 32 divisors (see below), whose sum is σ = 34032261120. Its totient is φ = 12211661952.

The previous prime is 21851683537. The next prime is 21851683547. The reversal of 21851683539 is 93538615812.

It is a happy number.

It is not a de Polignac number, because 21851683539 - 2¹ = 21851683537 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21851683491 and 21851683500.

It is not an unprimeable number, because it can be changed into a prime (21851683537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1402677 + ... + 1418169.

It is an arithmetic number, because the mean of its divisors is an integer number (1063508160).

Almost surely, 2^21851683539 is an apocalyptic number.

21851683539 is a deficient number, since it is larger than the sum of its proper divisors (12180577581).

21851683539 is a wasteful number, since it uses less digits than its factorization.

21851683539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16979.

The product of its digits is 1555200, while the sum is 51.

The spelling of 21851683539 in words is "twenty-one billion, eight hundred fifty-one million, six hundred eighty-three thousand, five hundred thirty-nine".