205623661 has 2 divisors, whose sum is σ = 205623662. Its totient is φ = 205623660.

The previous prime is 205623599. The next prime is 205623697. The reversal of 205623661 is 166326502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196168036 + 9455625 = 14006^2 + 3075^2 .

It is a cyclic number.

It is not a de Polignac number, because 205623661 - 2²¹ = 203526509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205623161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102811830 + 102811831.

It is an arithmetic number, because the mean of its divisors is an integer number (102811831).

Almost surely, 2^205623661 is an apocalyptic number.

It is an amenable number.

205623661 is a deficient number, since it is larger than the sum of its proper divisors (1).

205623661 is an equidigital number, since it uses as much as digits as its factorization.

205623661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 205623661 is about 14339.5837108334. The cubic root of 205623661 is about 590.2341893250.

The spelling of 205623661 in words is "two hundred five million, six hundred twenty-three thousand, six hundred sixty-one".