39821243021 has 6 divisors (see below), whose sum is σ = 46322670510. Its totient is φ = 34132493976.

The previous prime is 39821242997. The next prime is 39821243029. The reversal of 39821243021 is 12034212893.

It is a happy number.

39821243021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 23936421796 + 15884821225 = 154714^2 + 126035^2 .

It is not a de Polignac number, because 39821243021 - 2²⁶ = 39754134157 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 (39821243029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 406339166 + ... + 406339263.

It is an arithmetic number, because the mean of its divisors is an integer number (7720445085).

Almost surely, 2^39821243021 is an apocalyptic number.

It is an amenable number.

39821243021 is a deficient number, since it is larger than the sum of its proper divisors (6501427489).

39821243021 is an equidigital number, since it uses as much as digits as its factorization.

39821243021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812678443 (or 812678436 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The spelling of 39821243021 in words is "thirty-nine billion, eight hundred twenty-one million, two hundred forty-three thousand, twenty-one".