31212144521 has 4 divisors (see below), whose sum is σ = 31215361092. Its totient is φ = 31208927952.

The previous prime is 31212144463. The next prime is 31212144529. The reversal of 31212144521 is 12544121213.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26778049600 + 4434094921 = 163640^2 + 66589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31212144521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31212144529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1593686 + ... + 1613151.

It is an arithmetic number, because the mean of its divisors is an integer number (7803840273).

Almost surely, 2^31212144521 is an apocalyptic number.

It is an amenable number.

31212144521 is a deficient number, since it is larger than the sum of its proper divisors (3216571).

31212144521 is an equidigital number, since it uses as much as digits as its factorization.

31212144521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3216570.

The product of its digits is 1920, while the sum is 26.

Adding to 31212144521 its reverse (12544121213), we get a palindrome (43756265734).

The spelling of 31212144521 in words is "thirty-one billion, two hundred twelve million, one hundred forty-four thousand, five hundred twenty-one".