261854109 has 48 divisors (see below), whose sum is σ = 422547840. Its totient is φ = 154936320.

The previous prime is 261854107. The next prime is 261854113. The reversal of 261854109 is 901458162.

It is not a de Polignac number, because 261854109 - 2¹ = 261854107 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261854107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 995512 + ... + 995774.

It is an arithmetic number, because the mean of its divisors is an integer number (8803080).

Almost surely, 2^261854109 is an apocalyptic number.

It is an amenable number.

261854109 is a deficient number, since it is larger than the sum of its proper divisors (160693731).

261854109 is a wasteful number, since it uses less digits than its factorization.

261854109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 261854109 is about 16181.9068406662. The cubic root of 261854109 is about 639.7639990853.

The spelling of 261854109 in words is "two hundred sixty-one million, eight hundred fifty-four thousand, one hundred nine".