205689990 has 32 divisors (see below), whose sum is σ = 538534656. Its totient is φ = 49864160.

The previous prime is 205689977. The next prime is 205689997. The reversal of 205689990 is 99986502.

It is a super-3 number, since 3×205689990³ (a number of 26 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205689997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 311322 + ... + 311981.

It is an arithmetic number, because the mean of its divisors is an integer number (16829208).

Almost surely, 2^205689990 is an apocalyptic number.

205689990 is an abundant number, since it is smaller than the sum of its proper divisors (332844666).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205689990 is a wasteful number, since it uses less digits than its factorization.

205689990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623324.

The product of its (nonzero) digits is 349920, while the sum is 48.

The square root of 205689990 is about 14341.8963181303. The cubic root of 205689990 is about 590.2976473832.

The spelling of 205689990 in words is "two hundred five million, six hundred eighty-nine thousand, nine hundred ninety".