205689842 has 4 divisors (see below), whose sum is σ = 308534766. Its totient is φ = 102844920.

The previous prime is 205689821. The next prime is 205689859. The reversal of 205689842 is 248986502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 193794241 + 11895601 = 13921^2 + 3449^2 .

It is a super-2 number, since 2×205689842² = 84616622203969928, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 205689793 and 205689802.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51422459 + ... + 51422462.

Almost surely, 2^205689842 is an apocalyptic number.

205689842 is a deficient number, since it is larger than the sum of its proper divisors (102844924).

205689842 is a wasteful number, since it uses less digits than its factorization.

205689842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102844923.

The product of its (nonzero) digits is 276480, while the sum is 44.

The square root of 205689842 is about 14341.8911584212. The cubic root of 205689842 is about 590.2975058044.

The spelling of 205689842 in words is "two hundred five million, six hundred eighty-nine thousand, eight hundred forty-two".