21222012197 has 2 divisors, whose sum is σ = 21222012198. Its totient is φ = 21222012196.

The previous prime is 21222012193. The next prime is 21222012221. The reversal of 21222012197 is 79121022212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21148721476 + 73290721 = 145426^2 + 8561^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222012197 - 2² = 21222012193 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222012191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611006098 + 10611006099.

It is an arithmetic number, because the mean of its divisors is an integer number (10611006099).

Almost surely, 2^21222012197 is an apocalyptic number.

It is an amenable number.

21222012197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222012197 is an equidigital number, since it uses as much as digits as its factorization.

21222012197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 29.

The spelling of 21222012197 in words is "twenty-one billion, two hundred twenty-two million, twelve thousand, one hundred ninety-seven".