209220681 has 16 divisors (see below), whose sum is σ = 287089088. Its totient is φ = 135432000.

The previous prime is 209220653. The next prime is 209220691. The reversal of 209220681 is 186022902.

It is not a de Polignac number, because 209220681 - 2⁷ = 209220553 is a prime.

It is a super-2 number, since 2×209220681² = 87546586716207522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209220601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61731 + ... + 65031.

It is an arithmetic number, because the mean of its divisors is an integer number (17943068).

Almost surely, 2^209220681 is an apocalyptic number.

It is an amenable number.

209220681 is a deficient number, since it is larger than the sum of its proper divisors (77868407).

209220681 is a wasteful number, since it uses less digits than its factorization.

209220681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3912.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 209220681 is about 14464.4626930972. The cubic root of 209220681 is about 593.6560122181.

The spelling of 209220681 in words is "two hundred nine million, two hundred twenty thousand, six hundred eighty-one".