216697131594521 has 2 divisors, whose sum is σ = 216697131594522. Its totient is φ = 216697131594520.

The previous prime is 216697131594497. The next prime is 216697131594683. The reversal of 216697131594521 is 125495131796612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123252738705625 + 93444392888896 = 11101925^2 + 9666664^2 .

It is a cyclic number.

It is not a de Polignac number, because 216697131594521 - 2⁶ = 216697131594457 is a prime.

It is not a weakly prime, because it can be changed into another prime (216697131590521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108348565797260 + 108348565797261.

It is an arithmetic number, because the mean of its divisors is an integer number (108348565797261).

Almost surely, 2^{216697131594521} is an apocalyptic number.

It is an amenable number.

216697131594521 is a deficient number, since it is larger than the sum of its proper divisors (1).

216697131594521 is an equidigital number, since it uses as much as digits as its factorization.

216697131594521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24494400, while the sum is 62.

The spelling of 216697131594521 in words is "two hundred sixteen trillion, six hundred ninety-seven billion, one hundred thirty-one million, five hundred ninety-four thousand, five hundred twenty-one".