31440143221 has 4 divisors (see below), whose sum is σ = 31575079692. Its totient is φ = 31305206752.

The previous prime is 31440143209. The next prime is 31440143243. The reversal of 31440143221 is 12234104413.

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 4210192996 + 27229950225 = 64886^2 + 165015^2 .

It is a cyclic number.

It is not a de Polignac number, because 31440143221 - 2¹³ = 31440135029 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 (31440143261) 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, 67467886 + ... + 67468351.

It is an arithmetic number, because the mean of its divisors is an integer number (7893769923).

Almost surely, 2^31440143221 is an apocalyptic number.

It is an amenable number.

31440143221 is a deficient number, since it is larger than the sum of its proper divisors (134936471).

31440143221 is a wasteful number, since it uses less digits than its factorization.

31440143221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134936470.

The product of its (nonzero) digits is 2304, while the sum is 25.

Adding to 31440143221 its reverse (12234104413), we get a palindrome (43674247634).

The spelling of 31440143221 in words is "thirty-one billion, four hundred forty million, one hundred forty-three thousand, two hundred twenty-one".