210809985 has 16 divisors (see below), whose sum is σ = 337970880. Its totient is φ = 112207040.

The previous prime is 210809969. The next prime is 210810059. The reversal of 210809985 is 589908012.

It is a happy number.

It is not a de Polignac number, because 210809985 - 2⁴ = 210809969 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, 6171 + ... + 21440.

It is an arithmetic number, because the mean of its divisors is an integer number (21123180).

Almost surely, 2^210809985 is an apocalyptic number.

It is an amenable number.

210809985 is a deficient number, since it is larger than the sum of its proper divisors (127160895).

210809985 is a wasteful number, since it uses less digits than its factorization.

210809985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28128.

The product of its (nonzero) digits is 51840, while the sum is 42.

The square root of 210809985 is about 14519.2969871134. The cubic root of 210809985 is about 595.1554192306.

The spelling of 210809985 in words is "two hundred ten million, eight hundred nine thousand, nine hundred eighty-five".