31000000000 has 200 divisors, whose sum is σ = 79921866816. Its totient is φ = 12000000000.

The previous prime is 30999999997. The next prime is 31000000027. The reversal of 31000000000 is 13.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (200).

It is a super-2 number, since 2×31000000000² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (4).

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 999999985 + ... + 1000000015.

Almost surely, 2^31000000000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31000000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39960933408).

31000000000 is an abundant number, since it is smaller than the sum of its proper divisors (48921866816).

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

31000000000 is an frugal number, since it uses more digits than its factorization.

31000000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 3, while the sum is 4.

Adding to 31000000000 its reverse (13), we get a palindrome (31000000013).

The spelling of 31000000000 in words is "thirty-one billion", and thus it is an aban number and an uban number.