197797661 has 16 divisors (see below), whose sum is σ = 208830960. Its totient is φ = 187084800.

The previous prime is 197797637. The next prime is 197797673. The reversal of 197797661 is 166797791.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10272025 + 187525636 = 3205^2 + 13694^2 .

It is not a de Polignac number, because 197797661 - 2¹⁴ = 197781277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (197797361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 493061 + ... + 493461.

It is an arithmetic number, because the mean of its divisors is an integer number (13051935).

Almost surely, 2^197797661 is an apocalyptic number.

It is an amenable number.

197797661 is a deficient number, since it is larger than the sum of its proper divisors (11033299).

197797661 is a wasteful number, since it uses less digits than its factorization.

197797661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 736.

The product of its digits is 1000188, while the sum is 53.

The square root of 197797661 is about 14064.0556383996. The cubic root of 197797661 is about 582.6490605649.

The spelling of 197797661 in words is "one hundred ninety-seven million, seven hundred ninety-seven thousand, six hundred sixty-one".