31205213124 has 72 divisors (see below), whose sum is σ = 78437193408. Its totient is φ = 9651909120.

The previous prime is 31205213113. The next prime is 31205213147. The reversal of 31205213124 is 42131250213.

It is a super-2 number, since 2×31205213124² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31205213094 and 31205213103.

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 23 ways as a sum of consecutive naturals, for example, 182862 + ... + 309594.

It is an arithmetic number, because the mean of its divisors is an integer number (1089405464).

Almost surely, 2^31205213124 is an apocalyptic number.

31205213124 is a gapful number since it is divisible by the number (34) 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 31205213124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39218596704).

31205213124 is an abundant number, since it is smaller than the sum of its proper divisors (47231980284).

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

31205213124 is a wasteful number, since it uses less digits than its factorization.

31205213124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126845 (or 126826 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 31205213124 its reverse (42131250213), we get a palindrome (73336463337).

The spelling of 31205213124 in words is "thirty-one billion, two hundred five million, two hundred thirteen thousand, one hundred twenty-four".