19998785537669 has 2 divisors, whose sum is σ = 19998785537670. Its totient is φ = 19998785537668.

The previous prime is 19998785537657. The next prime is 19998785537683. The reversal of 19998785537669 is 96673558789991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17478670562500 + 2520114975169 = 4180750^2 + 1587487^2 .

It is a cyclic number.

It is not a de Polignac number, because 19998785537669 - 2⁴⁴ = 2406599493253 is a prime.

It is a super-2 number, since 2×19998785537669² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998785537869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999392768834 + 9999392768835.

It is an arithmetic number, because the mean of its divisors is an integer number (9999392768835).

Almost surely, 2^{19998785537669} is an apocalyptic number.

It is an amenable number.

19998785537669 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998785537669 is an equidigital number, since it uses as much as digits as its factorization.

19998785537669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55553299200, while the sum is 92.

The spelling of 19998785537669 in words is "nineteen trillion, nine hundred ninety-eight billion, seven hundred eighty-five million, five hundred thirty-seven thousand, six hundred sixty-nine".