31212111200021 has 4 divisors (see below), whose sum is σ = 31221129438444. Its totient is φ = 31203092961600.

The previous prime is 31212111199999. The next prime is 31212111200047. The reversal of 31212111200021 is 12000211121213.

It is a happy number.

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 10454164224100 + 20757946975921 = 3233290^2 + 4556089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31212111200021 is a prime.

It is a super-3 number, since 3×31212111200021³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31212111200051) 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, 4509114020 + ... + 4509120941.

It is an arithmetic number, because the mean of its divisors is an integer number (7805282359611).

Almost surely, 2^{31212111200021} is an apocalyptic number.

It is an amenable number.

31212111200021 is a deficient number, since it is larger than the sum of its proper divisors (9018238423).

31212111200021 is an equidigital number, since it uses as much as digits as its factorization.

31212111200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9018238422.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 31212111200021 its reverse (12000211121213), we get a palindrome (43212322321234).

The spelling of 31212111200021 in words is "thirty-one trillion, two hundred twelve billion, one hundred eleven million, two hundred thousand, twenty-one".