205717997 has 8 divisors (see below), whose sum is σ = 217349760. Its totient is φ = 194166720.

The previous prime is 205717979. The next prime is 205717999. The reversal of 205717997 is 799717502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205717997 - 2²⁴ = 188940781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205717999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14828 + ... + 25125.

It is an arithmetic number, because the mean of its divisors is an integer number (27168720).

Almost surely, 2^205717997 is an apocalyptic number.

It is an amenable number.

205717997 is a deficient number, since it is larger than the sum of its proper divisors (11631763).

205717997 is a wasteful number, since it uses less digits than its factorization.

205717997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40243.

The product of its (nonzero) digits is 277830, while the sum is 47.

The square root of 205717997 is about 14342.8726899460. The cubic root of 205717997 is about 590.3244380500.

The spelling of 205717997 in words is "two hundred five million, seven hundred seventeen thousand, nine hundred ninety-seven".