209085261 has 64 divisors (see below), whose sum is σ = 378224640. Its totient is φ = 99394560.

The previous prime is 209085257. The next prime is 209085311. The reversal of 209085261 is 162580902.

It is not a de Polignac number, because 209085261 - 2² = 209085257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209085061) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 144580 + ... + 146018.

It is an arithmetic number, because the mean of its divisors is an integer number (5909760).

Almost surely, 2^209085261 is an apocalyptic number.

209085261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

209085261 is a deficient number, since it is larger than the sum of its proper divisors (169139379).

209085261 is a wasteful number, since it uses less digits than its factorization.

209085261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1514.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 209085261 is about 14459.7808074673. The cubic root of 209085261 is about 593.5279014787.

The spelling of 209085261 in words is "two hundred nine million, eighty-five thousand, two hundred sixty-one".