12207866821 has 4 divisors (see below), whose sum is σ = 12925976652. Its totient is φ = 11489756992.

The previous prime is 12207866819. The next prime is 12207866843. The reversal of 12207866821 is 12866870221.

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 6774113025 + 5433753796 = 82305^2 + 73714^2 .

It is a cyclic number.

It is not a de Polignac number, because 12207866821 - 2¹ = 12207866819 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 (12207866861) 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, 359054890 + ... + 359054923.

It is an arithmetic number, because the mean of its divisors is an integer number (3231494163).

Almost surely, 2^12207866821 is an apocalyptic number.

It is an amenable number.

12207866821 is a deficient number, since it is larger than the sum of its proper divisors (718109831).

12207866821 is an equidigital number, since it uses as much as digits as its factorization.

12207866821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718109830.

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 12207866821 in words is "twelve billion, two hundred seven million, eight hundred sixty-six thousand, eight hundred twenty-one".