19744981 has 2 divisors, whose sum is σ = 19744982. Its totient is φ = 19744980.

The previous prime is 19744961. The next prime is 19744993. The reversal of 19744981 is 18944791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19722481 + 22500 = 4441^2 + 150^2 .

It is an emirp because it is prime and its reverse (18944791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19744981 - 2⁹ = 19744469 is a prime.

It is a super-2 number, since 2×19744981² = 779728549380722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19744951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9872490 + 9872491.

It is an arithmetic number, because the mean of its divisors is an integer number (9872491).

Almost surely, 2^19744981 is an apocalyptic number.

It is an amenable number.

19744981 is a deficient number, since it is larger than the sum of its proper divisors (1).

19744981 is an equidigital number, since it uses as much as digits as its factorization.

19744981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 43.

The square root of 19744981 is about 4443.5324911606. The cubic root of 19744981 is about 270.2831095336.

The spelling of 19744981 in words is "nineteen million, seven hundred forty-four thousand, nine hundred eighty-one".