197761021 has 2 divisors, whose sum is σ = 197761022. Its totient is φ = 197761020.

The previous prime is 197761013. The next prime is 197761037. The reversal of 197761021 is 120167791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155002500 + 42758521 = 12450^2 + 6539^2 .

It is an emirp because it is prime and its reverse (120167791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 197761021 - 2³ = 197761013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197761001) 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, 98880510 + 98880511.

It is an arithmetic number, because the mean of its divisors is an integer number (98880511).

Almost surely, 2^197761021 is an apocalyptic number.

It is an amenable number.

197761021 is a deficient number, since it is larger than the sum of its proper divisors (1).

197761021 is an equidigital number, since it uses as much as digits as its factorization.

197761021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5292, while the sum is 34.

The square root of 197761021 is about 14062.7529666136. The cubic root of 197761021 is about 582.6130817439.

The spelling of 197761021 in words is "one hundred ninety-seven million, seven hundred sixty-one thousand, twenty-one".