31123210212 has 18 divisors (see below), whose sum is σ = 78672559238. Its totient is φ = 10374403392.

The previous prime is 31123210201. The next prime is 31123210259. The reversal of 31123210212 is 21201232113.

It can be written as a sum of positive squares in only one way, i.e., 22926805056 + 8196405156 = 151416^2 + 90534^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 432266773 + ... + 432266844.

Almost surely, 2^31123210212 is an apocalyptic number.

It is an amenable number.

31123210212 is an abundant number, since it is smaller than the sum of its proper divisors (47549349026).

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

31123210212 is a wasteful number, since it uses less digits than its factorization.

31123210212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864533627 (or 864533622 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 31123210212 its reverse (21201232113), we get a palindrome (52324442325).

The spelling of 31123210212 in words is "thirty-one billion, one hundred twenty-three million, two hundred ten thousand, two hundred twelve".