21543985839 has 8 divisors (see below), whose sum is σ = 28745852800. Its totient is φ = 14352388056.

The previous prime is 21543985783. The next prime is 21543985849. The reversal of 21543985839 is 93858934512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21543985839 - 2⁹ = 21543985327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21543985849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2562397 + ... + 2570790.

It is an arithmetic number, because the mean of its divisors is an integer number (3593231600).

Almost surely, 2^21543985839 is an apocalyptic number.

21543985839 is a deficient number, since it is larger than the sum of its proper divisors (7201866961).

21543985839 is a wasteful number, since it uses less digits than its factorization.

21543985839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5134589.

The product of its digits is 9331200, while the sum is 57.

The spelling of 21543985839 in words is "twenty-one billion, five hundred forty-three million, nine hundred eighty-five thousand, eight hundred thirty-nine".