31131243221 has 8 divisors (see below), whose sum is σ = 33533359104. Its totient is φ = 28730185200.

The previous prime is 31131243211. The next prime is 31131243257. The reversal of 31131243221 is 12234213113.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31131243221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131243211) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 202805 + ... + 321546.

It is an arithmetic number, because the mean of its divisors is an integer number (4191669888).

Almost surely, 2^31131243221 is an apocalyptic number.

It is an amenable number.

31131243221 is a deficient number, since it is larger than the sum of its proper divisors (2402115883).

31131243221 is a wasteful number, since it uses less digits than its factorization.

31131243221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528931.

The product of its digits is 864, while the sum is 23.

Adding to 31131243221 its reverse (12234213113), we get a palindrome (43365456334).

The spelling of 31131243221 in words is "thirty-one billion, one hundred thirty-one million, two hundred forty-three thousand, two hundred twenty-one".