31121200000 has 288 divisors, whose sum is σ = 85311961560. Its totient is φ = 11299200000.

The previous prime is 31121199979. The next prime is 31121200001. The reversal of 31121200000 is 212113.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 31121200000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121200001) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 48399679 + ... + 48400321.

Almost surely, 2^31121200000 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 31121200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42655980780).

31121200000 is an abundant number, since it is smaller than the sum of its proper divisors (54190761560).

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

31121200000 is an frugal number, since it uses more digits than its factorization.

31121200000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704 (or 661 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 31121200000 its reverse (212113), we get a palindrome (31121412113).

The spelling of 31121200000 in words is "thirty-one billion, one hundred twenty-one million, two hundred thousand".