31312100221 has 8 divisors (see below), whose sum is σ = 31822949120. Its totient is φ = 30804113808.

The previous prime is 31312100147. The next prime is 31312100293. The reversal of 31312100221 is 12200121313.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31312100221 - 2¹³ = 31312092029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31312100195 and 31312100204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31312100621) 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, 693561 + ... + 737326.

It is an arithmetic number, because the mean of its divisors is an integer number (3977868640).

Almost surely, 2^31312100221 is an apocalyptic number.

It is an amenable number.

31312100221 is a deficient number, since it is larger than the sum of its proper divisors (510848899).

31312100221 is a wasteful number, since it uses less digits than its factorization.

31312100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1431243.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 31312100221 its reverse (12200121313), we get a palindrome (43512221534).

The spelling of 31312100221 in words is "thirty-one billion, three hundred twelve million, one hundred thousand, two hundred twenty-one".