19885681 has 2 divisors, whose sum is σ = 19885682. Its totient is φ = 19885680.

The previous prime is 19885661. The next prime is 19885703. The reversal of 19885681 is 18658891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 349281 = 4420^2 + 591^2 .

It is an emirp because it is prime and its reverse (18658891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19885681 - 2¹⁵ = 19852913 is a prime.

It is a super-2 number, since 2×19885681² = 790880617667522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19885661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9942840 + 9942841.

It is an arithmetic number, because the mean of its divisors is an integer number (9942841).

Almost surely, 2^19885681 is an apocalyptic number.

It is an amenable number.

19885681 is a deficient number, since it is larger than the sum of its proper divisors (1).

19885681 is an equidigital number, since it uses as much as digits as its factorization.

19885681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 46.

The square root of 19885681 is about 4459.3363856072. The cubic root of 19885681 is about 270.9235906094.

The spelling of 19885681 in words is "nineteen million, eight hundred eighty-five thousand, six hundred eighty-one".