21210116197 has 2 divisors, whose sum is σ = 21210116198. Its totient is φ = 21210116196.

The previous prime is 21210116189. The next prime is 21210116261. The reversal of 21210116197 is 79161101212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13315082881 + 7895033316 = 115391^2 + 88854^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210116197 - 2³ = 21210116189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210116297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605058098 + 10605058099.

It is an arithmetic number, because the mean of its divisors is an integer number (10605058099).

Almost surely, 2^21210116197 is an apocalyptic number.

It is an amenable number.

21210116197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210116197 is an equidigital number, since it uses as much as digits as its factorization.

21210116197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 31.

The spelling of 21210116197 in words is "twenty-one billion, two hundred ten million, one hundred sixteen thousand, one hundred ninety-seven".