31431201221 has 8 divisors (see below), whose sum is σ = 35937875520. Its totient is φ = 26928652608.

The previous prime is 31431201211. The next prime is 31431201223. The reversal of 31431201221 is 12210213413.

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-31431201221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31431201193 and 31431201202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31431201223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1015076 + ... + 1045581.

It is an arithmetic number, because the mean of its divisors is an integer number (4492234440).

Almost surely, 2^31431201221 is an apocalyptic number.

It is an amenable number.

31431201221 is a deficient number, since it is larger than the sum of its proper divisors (4506674299).

31431201221 is a wasteful number, since it uses less digits than its factorization.

31431201221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2062843.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 31431201221 its reverse (12210213413), we get a palindrome (43641414634).

The spelling of 31431201221 in words is "thirty-one billion, four hundred thirty-one million, two hundred one thousand, two hundred twenty-one".