209951985 has 16 divisors (see below), whose sum is σ = 339007680. Its totient is φ = 110946240.

The previous prime is 209951947. The next prime is 209952019. The reversal of 209951985 is 589159902.

It is a happy number.

209951985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 209951985 - 2¹⁵ = 209919217 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62571 + ... + 65840.

It is an arithmetic number, because the mean of its divisors is an integer number (21187980).

Almost surely, 2^209951985 is an apocalyptic number.

It is an amenable number.

209951985 is a deficient number, since it is larger than the sum of its proper divisors (129055695).

209951985 is a wasteful number, since it uses less digits than its factorization.

209951985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128528.

The product of its (nonzero) digits is 291600, while the sum is 48.

The square root of 209951985 is about 14489.7199765903. The cubic root of 209951985 is about 594.3468906467.

The spelling of 209951985 in words is "two hundred nine million, nine hundred fifty-one thousand, nine hundred eighty-five".