204978161 has 2 divisors, whose sum is σ = 204978162. Its totient is φ = 204978160.

The previous prime is 204978133. The next prime is 204978173. The reversal of 204978161 is 161879402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 187169761 + 17808400 = 13681^2 + 4220^2 .

It is a cyclic number.

It is not a de Polignac number, because 204978161 - 2²² = 200783857 is a prime.

It is not a weakly prime, because it can be changed into another prime (204978131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102489080 + 102489081.

It is an arithmetic number, because the mean of its divisors is an integer number (102489081).

Almost surely, 2^204978161 is an apocalyptic number.

It is an amenable number.

204978161 is a deficient number, since it is larger than the sum of its proper divisors (1).

204978161 is an equidigital number, since it uses as much as digits as its factorization.

204978161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 204978161 is about 14317.0583920022. The cubic root of 204978161 is about 589.6159149132.

The spelling of 204978161 in words is "two hundred four million, nine hundred seventy-eight thousand, one hundred sixty-one".