99981831690 has 96 divisors (see below), whose sum is σ = 280246009680. Its totient is φ = 24584813568.

The previous prime is 99981831629. The next prime is 99981831707. The reversal of 99981831690 is 9613818999.

It can be written as a sum of positive squares in 8 ways, for example, as 12698810721 + 87283020969 = 112689^2 + 295437^2 .

It is a super-2 number, since 2×99981831690² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1070176 + ... + 1159844.

Almost surely, 2^99981831690 is an apocalyptic number.

99981831690 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 99981831690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140123004840).

99981831690 is an abundant number, since it is smaller than the sum of its proper divisors (180264177990).

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

99981831690 is a wasteful number, since it uses less digits than its factorization.

99981831690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90648 (or 90645 counting only the distinct ones).

The product of its (nonzero) digits is 7558272, while the sum is 63.

The spelling of 99981831690 in words is "ninety-nine billion, nine hundred eighty-one million, eight hundred thirty-one thousand, six hundred ninety".