31121100000 has 432 divisors, whose sum is σ = 111837529440. Its totient is φ = 8208000000.

The previous prime is 31121099983. The next prime is 31121100001. The reversal of 31121100000 is 112113.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121100001) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 135899886 + ... + 135900114.

It is an arithmetic number, because the mean of its divisors is an integer number (258883170).

Almost surely, 2^31121100000 is an apocalyptic number.

31121100000 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31121100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55918764720).

31121100000 is an abundant number, since it is smaller than the sum of its proper divisors (80716429440).

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

31121100000 is a wasteful number, since it uses less digits than its factorization.

31121100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

Adding to 31121100000 its reverse (112113), we get a palindrome (31121212113).

The spelling of 31121100000 in words is "thirty-one billion, one hundred twenty-one million, one hundred thousand".