209663081 has 8 divisors (see below), whose sum is σ = 223722720. Its totient is φ = 195905952.

The previous prime is 209663021. The next prime is 209663093. The reversal of 209663081 is 180366902.

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 209663081 - 2²² = 205468777 is a prime.

It is a super-2 number, since 2×209663081² = 87917215068825122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (209663021) 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, 74195 + ... + 76968.

It is an arithmetic number, because the mean of its divisors is an integer number (27965340).

Almost surely, 2^209663081 is an apocalyptic number.

It is an amenable number.

209663081 is a deficient number, since it is larger than the sum of its proper divisors (14059639).

209663081 is a wasteful number, since it uses less digits than its factorization.

209663081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151255.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 209663081 is about 14479.7472698939. The cubic root of 209663081 is about 594.0741488983.

The spelling of 209663081 in words is "two hundred nine million, six hundred sixty-three thousand, eighty-one".