19708981 has 2 divisors, whose sum is σ = 19708982. Its totient is φ = 19708980.

The previous prime is 19708943. The next prime is 19708991. The reversal of 19708981 is 18980791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17926756 + 1782225 = 4234^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 19708981 - 2¹⁵ = 19676213 is a prime.

It is a super-2 number, since 2×19708981² = 776887864116722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19708991) 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, 9854490 + 9854491.

It is an arithmetic number, because the mean of its divisors is an integer number (9854491).

Almost surely, 2^19708981 is an apocalyptic number.

It is an amenable number.

19708981 is a deficient number, since it is larger than the sum of its proper divisors (1).

19708981 is an equidigital number, since it uses as much as digits as its factorization.

19708981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 43.

The square root of 19708981 is about 4439.4798118699. The cubic root of 19708981 is about 270.1187452080.

The spelling of 19708981 in words is "nineteen million, seven hundred eight thousand, nine hundred eighty-one".