16931217989221 has 2 divisors, whose sum is σ = 16931217989222. Its totient is φ = 16931217989220.

The previous prime is 16931217989207. The next prime is 16931217989227. The reversal of 16931217989221 is 12298971213961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8482574700196 + 8448643289025 = 2912486^2 + 2906655^2 .

It is a cyclic number.

It is not a de Polignac number, because 16931217989221 - 2³⁹ = 16381462175333 is a prime.

It is a super-2 number, since 2×16931217989221² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16931217989221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16931217989227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8465608994610 + 8465608994611.

It is an arithmetic number, because the mean of its divisors is an integer number (8465608994611).

Almost surely, 2^{16931217989221} is an apocalyptic number.

It is an amenable number.

16931217989221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16931217989221 is an equidigital number, since it uses as much as digits as its factorization.

16931217989221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5878656, while the sum is 61.

The spelling of 16931217989221 in words is "sixteen trillion, nine hundred thirty-one billion, two hundred seventeen million, nine hundred eighty-nine thousand, two hundred twenty-one".