821212212127 has 4 divisors (see below), whose sum is σ = 835131063240. Its totient is φ = 807293361016.

The previous prime is 821212212077. The next prime is 821212212137. The reversal of 821212212127 is 721212212128.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 821212212127 - 2⁷ = 821212211999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821212212137) 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, 6959425468 + ... + 6959425585.

It is an arithmetic number, because the mean of its divisors is an integer number (208782765810).

Almost surely, 2^821212212127 is an apocalyptic number.

821212212127 is a deficient number, since it is larger than the sum of its proper divisors (13918851113).

821212212127 is a wasteful number, since it uses less digits than its factorization.

821212212127 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13918851112.

The product of its digits is 3584, while the sum is 31.

Subtracting from 821212212127 its reverse (721212212128), we obtain a palindrome (99999999999).

The spelling of 821212212127 in words is "eight hundred twenty-one billion, two hundred twelve million, two hundred twelve thousand, one hundred twenty-seven".