31999999806 has 96 divisors (see below), whose sum is σ = 73967781888. Its totient is φ = 10362764160.

The previous prime is 31999999777. The next prime is 31999999813. The reversal of 31999999806 is 60899999913.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3987510 + ... + 3995526.

It is an arithmetic number, because the mean of its divisors is an integer number (770497728).

Almost surely, 2^31999999806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31999999806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36983890944).

31999999806 is an abundant number, since it is smaller than the sum of its proper divisors (41967782082).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31999999806 is a wasteful number, since it uses less digits than its factorization.

31999999806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8268 (or 8256 counting only the distinct ones).

The product of its (nonzero) digits is 76527504, while the sum is 72.

The spelling of 31999999806 in words is "thirty-one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred six".