39931228813 has 6 divisors (see below), whose sum is σ = 46450613166. Its totient is φ = 34226767512.

The previous prime is 39931228807. The next prime is 39931228829. The reversal of 39931228813 is 31882213993.

It can be written as a sum of positive squares in only one way, i.e., 30280524169 + 9650704644 = 174013^2 + 98238^2 .

It is a de Polignac number, because none of the positive numbers 2^k-39931228813 is a prime.

It is a super-2 number, since 2×39931228813² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 814923037 = 39931228813 / (3 + 9 + 9 + 3 + 1 + 2 + 2 + 8 + 8 + 1 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39931228873) 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, 407461470 + ... + 407461567.

It is an arithmetic number, because the mean of its divisors is an integer number (7741768861).

Almost surely, 2^39931228813 is an apocalyptic number.

It is an amenable number.

39931228813 is a deficient number, since it is larger than the sum of its proper divisors (6519384353).

39931228813 is an equidigital number, since it uses as much as digits as its factorization.

39931228813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814923051 (or 814923044 counting only the distinct ones).

The product of its digits is 559872, while the sum is 49.

The spelling of 39931228813 in words is "thirty-nine billion, nine hundred thirty-one million, two hundred twenty-eight thousand, eight hundred thirteen".