197645521 has 2 divisors, whose sum is σ = 197645522. Its totient is φ = 197645520.

The previous prime is 197645489. The next prime is 197645531. The reversal of 197645521 is 125546791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144865296 + 52780225 = 12036^2 + 7265^2 .

It is a cyclic number.

It is not a de Polignac number, because 197645521 - 2⁵ = 197645489 is a prime.

It is a super-2 number, since 2×197645521² = 78127503942722882, which contains 22 as substring.

It is a Chen prime.

It is equal to p_10955758 and since 197645521 and 10955758 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (197645531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98822760 + 98822761.

It is an arithmetic number, because the mean of its divisors is an integer number (98822761).

Almost surely, 2^197645521 is an apocalyptic number.

It is an amenable number.

197645521 is a deficient number, since it is larger than the sum of its proper divisors (1).

197645521 is an equidigital number, since it uses as much as digits as its factorization.

197645521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75600, while the sum is 40.

The square root of 197645521 is about 14058.6457740424. The cubic root of 197645521 is about 582.4996368814.

The spelling of 197645521 in words is "one hundred ninety-seven million, six hundred forty-five thousand, five hundred twenty-one".