31220012221 has 4 divisors (see below), whose sum is σ = 31222193632. Its totient is φ = 31217830812.

The previous prime is 31220012141. The next prime is 31220012249. The reversal of 31220012221 is 12221002213.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31220012221 - 2¹⁹ = 31219487933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31220012195 and 31220012204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220012281) 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, 1069095 + ... + 1097908.

It is an arithmetic number, because the mean of its divisors is an integer number (7805548408).

Almost surely, 2^31220012221 is an apocalyptic number.

It is an amenable number.

31220012221 is a deficient number, since it is larger than the sum of its proper divisors (2181411).

31220012221 is a wasteful number, since it uses less digits than its factorization.

31220012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2181410.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 31220012221 its reverse (12221002213), we get a palindrome (43441014434).

The spelling of 31220012221 in words is "thirty-one billion, two hundred twenty million, twelve thousand, two hundred twenty-one".