21639839145 has 16 divisors (see below), whose sum is σ = 34626465792. Its totient is φ = 11540339840.

The previous prime is 21639839131. The next prime is 21639839149. The reversal of 21639839145 is 54193893612.

It is not a de Polignac number, because 21639839145 - 2¹¹ = 21639837097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21639839149) 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 15 ways as a sum of consecutive naturals, for example, 169429 + ... + 268301.

It is an arithmetic number, because the mean of its divisors is an integer number (2164154112).

Almost surely, 2^21639839145 is an apocalyptic number.

It is an amenable number.

21639839145 is a deficient number, since it is larger than the sum of its proper divisors (12986626647).

21639839145 is a wasteful number, since it uses less digits than its factorization.

21639839145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113472.

The product of its digits is 1399680, while the sum is 51.

The spelling of 21639839145 in words is "twenty-one billion, six hundred thirty-nine million, eight hundred thirty-nine thousand, one hundred forty-five".