31100123121221 has 48 divisors (see below), whose sum is σ = 39728810741760. Its totient is φ = 24073030084320.

The previous prime is 31100123121181. The next prime is 31100123121239. The reversal of 31100123121221 is 12212132100113.

It is not a de Polignac number, because 31100123121221 - 2¹⁴ = 31100123104837 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31100123121193 and 31100123121202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31100123121521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 138778100 + ... + 139002018.

It is an arithmetic number, because the mean of its divisors is an integer number (827683557120).

Almost surely, 2^{31100123121221} is an apocalyptic number.

It is an amenable number.

31100123121221 is a deficient number, since it is larger than the sum of its proper divisors (8628687620539).

31100123121221 is a wasteful number, since it uses less digits than its factorization.

31100123121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225654 (or 225647 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 31100123121221 its reverse (12212132100113), we get a palindrome (43312255221334).

The spelling of 31100123121221 in words is "thirty-one trillion, one hundred billion, one hundred twenty-three million, one hundred twenty-one thousand, two hundred twenty-one".