31244151221 has 6 divisors (see below), whose sum is σ = 31374391266. Its totient is φ = 31114449600.

The previous prime is 31244151217. The next prime is 31244151227. The reversal of 31244151221 is 12215144213.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 20750402500 + 10493748721 = 144050^2 + 102439^2 .

It is not a de Polignac number, because 31244151221 - 2² = 31244151217 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 (31244151227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 210890 + ... + 327051.

It is an arithmetic number, because the mean of its divisors is an integer number (5229065211).

Almost surely, 2^31244151221 is an apocalyptic number.

It is an amenable number.

31244151221 is a deficient number, since it is larger than the sum of its proper divisors (130240045).

31244151221 is an frugal number, since it uses more digits than its factorization.

31244151221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538423 (or 538182 counting only the distinct ones).

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

Adding to 31244151221 its reverse (12215144213), we get a palindrome (43459295434).

The spelling of 31244151221 in words is "thirty-one billion, two hundred forty-four million, one hundred fifty-one thousand, two hundred twenty-one".