312121220051 has 4 divisors (see below), whose sum is σ = 312220719912. Its totient is φ = 312021720192.

The previous prime is 312121220011. The next prime is 312121220071. The reversal of 312121220051 is 150022121213.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-312121220051 is a prime.

It is a super-2 number, since 2×312121220051² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (312121220011) 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, 49745225 + ... + 49751498.

It is an arithmetic number, because the mean of its divisors is an integer number (78055179978).

Almost surely, 2^312121220051 is an apocalyptic number.

312121220051 is a deficient number, since it is larger than the sum of its proper divisors (99499861).

312121220051 is an equidigital number, since it uses as much as digits as its factorization.

312121220051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99499860.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 312121220051 its reverse (150022121213), we get a palindrome (462143341264).

The spelling of 312121220051 in words is "three hundred twelve billion, one hundred twenty-one million, two hundred twenty thousand, fifty-one".