196549781581 has 2 divisors, whose sum is σ = 196549781582. Its totient is φ = 196549781580.

The previous prime is 196549781489. The next prime is 196549781591. The reversal of 196549781581 is 185187945691.

196549781581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195726608100 + 823173481 = 442410^2 + 28691^2 .

It is a cyclic number.

It is not a de Polignac number, because 196549781581 - 2⁹ = 196549781069 is a prime.

It is a super-2 number, since 2×196549781581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (196549781591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98274890790 + 98274890791.

It is an arithmetic number, because the mean of its divisors is an integer number (98274890791).

Almost surely, 2^196549781581 is an apocalyptic number.

It is an amenable number.

196549781581 is a deficient number, since it is larger than the sum of its proper divisors (1).

196549781581 is an equidigital number, since it uses as much as digits as its factorization.

196549781581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21772800, while the sum is 64.

The spelling of 196549781581 in words is "one hundred ninety-six billion, five hundred forty-nine million, seven hundred eighty-one thousand, five hundred eighty-one".