205664042 has 4 divisors (see below), whose sum is σ = 308496066. Its totient is φ = 102832020.

The previous prime is 205664033. The next prime is 205664047. The reversal of 205664042 is 240466502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 240466502 = 2 ⋅120233251.

It can be written as a sum of positive squares in only one way, i.e., 205606921 + 57121 = 14339^2 + 239^2 .

It is a junction number, because it is equal to n+sod(n) for n = 205663996 and 205664014.

It is not an unprimeable number, because it can be changed into a prime (205664047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51416009 + ... + 51416012.

Almost surely, 2^205664042 is an apocalyptic number.

205664042 is a deficient number, since it is larger than the sum of its proper divisors (102832024).

205664042 is a wasteful number, since it uses less digits than its factorization.

205664042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102832023.

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 205664042 is about 14340.9916672453. The cubic root of 205664042 is about 590.2728241246.

The spelling of 205664042 in words is "two hundred five million, six hundred sixty-four thousand, forty-two".