39918481993 has 4 divisors (see below), whose sum is σ = 42989134468. Its totient is φ = 36847829520.

The previous prime is 39918481973. The next prime is 39918482057.

39918481993 is nontrivially palindromic in base 10.

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 20705195449 + 19213286544 = 143893^2 + 138612^2 .

It is a cyclic number.

It is not a de Polignac number, because 39918481993 - 2²¹ = 39916384841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39918481973) 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 3 ways as a sum of consecutive naturals, for example, 1535326218 + ... + 1535326243.

It is an arithmetic number, because the mean of its divisors is an integer number (10747283617).

Almost surely, 2^39918481993 is an apocalyptic number.

It is an amenable number.

39918481993 is a deficient number, since it is larger than the sum of its proper divisors (3070652475).

39918481993 is a wasteful number, since it uses less digits than its factorization.

39918481993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3070652474.

The product of its digits is 15116544, while the sum is 64.

The spelling of 39918481993 in words is "thirty-nine billion, nine hundred eighteen million, four hundred eighty-one thousand, nine hundred ninety-three".