39643678821 has 8 divisors (see below), whose sum is σ = 52859659104. Its totient is φ = 26428408880.

The previous prime is 39643678813. The next prime is 39643678829. The reversal of 39643678821 is 12887634693.

It is an interprime number because it is at equal distance from previous prime (39643678813) and next prime (39643678829).

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

It is a cyclic number.

It is not a de Polignac number, because 39643678821 - 2³ = 39643678813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39643678829) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 29790 + ... + 283151.

It is an arithmetic number, because the mean of its divisors is an integer number (6607457388).

Almost surely, 2^39643678821 is an apocalyptic number.

It is an amenable number.

39643678821 is a deficient number, since it is larger than the sum of its proper divisors (13215980283).

39643678821 is a wasteful number, since it uses less digits than its factorization.

39643678821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355171.

The product of its digits is 10450944, while the sum is 57.

The spelling of 39643678821 in words is "thirty-nine billion, six hundred forty-three million, six hundred seventy-eight thousand, eight hundred twenty-one".