209935081 has 2 divisors, whose sum is σ = 209935082. Its totient is φ = 209935080.

The previous prime is 209935051. The next prime is 209935087. The reversal of 209935081 is 180539902.

209935081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 190881856 + 19053225 = 13816^2 + 4365^2 .

It is a cyclic number.

It is not a de Polignac number, because 209935081 - 2⁵ = 209935049 is a prime.

It is a super-2 number, since 2×209935081² = 88145476468953122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 209935081.

It is not a weakly prime, because it can be changed into another prime (209935087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104967540 + 104967541.

It is an arithmetic number, because the mean of its divisors is an integer number (104967541).

Almost surely, 2^209935081 is an apocalyptic number.

It is an amenable number.

209935081 is a deficient number, since it is larger than the sum of its proper divisors (1).

209935081 is an equidigital number, since it uses as much as digits as its factorization.

209935081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 209935081 is about 14489.1366547493. The cubic root of 209935081 is about 594.3309392067.

The spelling of 209935081 in words is "two hundred nine million, nine hundred thirty-five thousand, eighty-one".