39840637849 has 4 divisors (see below), whose sum is σ = 39842635300. Its totient is φ = 39838640400.

The previous prime is 39840637847. The next prime is 39840637853. The reversal of 39840637849 is 94873604893.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 23531560000 + 16309077849 = 153400^2 + 127707^2 .

It is a cyclic number.

It is not a de Polignac number, because 39840637849 - 2¹ = 39840637847 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39840637843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 968502 + ... + 1008799.

It is an arithmetic number, because the mean of its divisors is an integer number (9960658825).

Almost surely, 2^39840637849 is an apocalyptic number.

It is an amenable number.

39840637849 is a deficient number, since it is larger than the sum of its proper divisors (1997451).

39840637849 is a wasteful number, since it uses less digits than its factorization.

39840637849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997450.

The product of its (nonzero) digits is 31352832, while the sum is 61.

The spelling of 39840637849 in words is "thirty-nine billion, eight hundred forty million, six hundred thirty-seven thousand, eight hundred forty-nine".