209705641 has 8 divisors (see below), whose sum is σ = 228355200. Its totient is φ = 191817360.

The previous prime is 209705623. The next prime is 209705653. The reversal of 209705641 is 146507902.

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 209705641 - 2¹⁷ = 209574569 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209705597 and 209705606.

It is not an unprimeable number, because it can be changed into a prime (209705141) 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, 189745 + ... + 190846.

It is an arithmetic number, because the mean of its divisors is an integer number (28544400).

Almost surely, 2^209705641 is an apocalyptic number.

It is an amenable number.

209705641 is a deficient number, since it is larger than the sum of its proper divisors (18649559).

209705641 is a wasteful number, since it uses less digits than its factorization.

209705641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380639.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 209705641 is about 14481.2168342305. The cubic root of 209705641 is about 594.1143436798.

The spelling of 209705641 in words is "two hundred nine million, seven hundred five thousand, six hundred forty-one".