19880981 has 2 divisors, whose sum is σ = 19880982. Its totient is φ = 19880980.

The previous prime is 19880963. The next prime is 19881019. The reversal of 19880981 is 18908891.

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., 19061956 + 819025 = 4366^2 + 905^2 .

It is an emirp because it is prime and its reverse (18908891) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 18608861 and 16880681.

It is a cyclic number.

It is not a de Polignac number, because 19880981 - 2²² = 15686677 is a prime.

It is a super-2 number, since 2×19880981² = 790506811044722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19880911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9940490 + 9940491.

It is an arithmetic number, because the mean of its divisors is an integer number (9940491).

Almost surely, 2^19880981 is an apocalyptic number.

It is an amenable number.

19880981 is a deficient number, since it is larger than the sum of its proper divisors (1).

19880981 is an equidigital number, since it uses as much as digits as its factorization.

19880981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 19880981 is about 4458.8093702243. The cubic root of 19880981 is about 270.9022445764.

The spelling of 19880981 in words is "nineteen million, eight hundred eighty thousand, nine hundred eighty-one".