31212120 has 64 divisors (see below), whose sum is σ = 96876000. Its totient is φ = 8035328.

The previous prime is 31212113. The next prime is 31212143. The reversal of 31212120 is 2121213.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31212096 and 31212105.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1005 + ... + 7964.

Almost surely, 2^31212120 is an apocalyptic number.

31212120 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 31212120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48438000).

31212120 is an abundant number, since it is smaller than the sum of its proper divisors (65663880).

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

31212120 is a wasteful number, since it uses less digits than its factorization.

31212120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9012 (or 9008 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 31212120 is about 5586.7808262004. The cubic root of 31212120 is about 314.8529421907.

Adding to 31212120 its reverse (2121213), we get a palindrome (33333333).

The spelling of 31212120 in words is "thirty-one million, two hundred twelve thousand, one hundred twenty".