12205291621 has 2 divisors, whose sum is σ = 12205291622. Its totient is φ = 12205291620.

The previous prime is 12205291543. The next prime is 12205291663. The reversal of 12205291621 is 12619250221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12120909025 + 84382596 = 110095^2 + 9186^2 .

It is a cyclic number.

It is not a de Polignac number, because 12205291621 - 2¹³ = 12205283429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12205291691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6102645810 + 6102645811.

It is an arithmetic number, because the mean of its divisors is an integer number (6102645811).

Almost surely, 2^12205291621 is an apocalyptic number.

It is an amenable number.

12205291621 is a deficient number, since it is larger than the sum of its proper divisors (1).

12205291621 is an equidigital number, since it uses as much as digits as its factorization.

12205291621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 12205291621 in words is "twelve billion, two hundred five million, two hundred ninety-one thousand, six hundred twenty-one".