21210201195817 has 2 divisors, whose sum is σ = 21210201195818. Its totient is φ = 21210201195816.

The previous prime is 21210201195791. The next prime is 21210201195863. The reversal of 21210201195817 is 71859110201212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21181248131481 + 28953064336 = 4602309^2 + 170156^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210201195817 - 2¹⁹ = 21210200671529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210201195817.

It is not a weakly prime, because it can be changed into another prime (21210201195917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605100597908 + 10605100597909.

It is an arithmetic number, because the mean of its divisors is an integer number (10605100597909).

Almost surely, 2^{21210201195817} is an apocalyptic number.

It is an amenable number.

21210201195817 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210201195817 is an equidigital number, since it uses as much as digits as its factorization.

21210201195817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 40.

The spelling of 21210201195817 in words is "twenty-one trillion, two hundred ten billion, two hundred one million, one hundred ninety-five thousand, eight hundred seventeen".