197959661 has 2 divisors, whose sum is σ = 197959662. Its totient is φ = 197959660.

The previous prime is 197959649. The next prime is 197959687. The reversal of 197959661 is 166959791.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134119561 + 63840100 = 11581^2 + 7990^2 .

It is an emirp because it is prime and its reverse (166959791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 197959661 - 2¹⁸ = 197697517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197959621) 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, 98979830 + 98979831.

It is an arithmetic number, because the mean of its divisors is an integer number (98979831).

Almost surely, 2^197959661 is an apocalyptic number.

It is an amenable number.

197959661 is a deficient number, since it is larger than the sum of its proper divisors (1).

197959661 is an equidigital number, since it uses as much as digits as its factorization.

197959661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 918540, while the sum is 53.

The square root of 197959661 is about 14069.8138225067. The cubic root of 197959661 is about 582.8080840003.

The spelling of 197959661 in words is "one hundred ninety-seven million, nine hundred fifty-nine thousand, six hundred sixty-one".