19986541 has 2 divisors, whose sum is σ = 19986542. Its totient is φ = 19986540.

The previous prime is 19986523. The next prime is 19986581. The reversal of 19986541 is 14568991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19802500 + 184041 = 4450^2 + 429^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19986541 is a prime.

It is a super-2 number, since 2×19986541² = 798923642289362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19986581) 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, 9993270 + 9993271.

It is an arithmetic number, because the mean of its divisors is an integer number (9993271).

Almost surely, 2^19986541 is an apocalyptic number.

It is an amenable number.

19986541 is a deficient number, since it is larger than the sum of its proper divisors (1).

19986541 is an equidigital number, since it uses as much as digits as its factorization.

19986541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 43.

The square root of 19986541 is about 4470.6309398115. The cubic root of 19986541 is about 271.3808590848.

The spelling of 19986541 in words is "nineteen million, nine hundred eighty-six thousand, five hundred forty-one".