261800087 has 4 divisors (see below), whose sum is σ = 261981720. Its totient is φ = 261618456.

The previous prime is 261800059. The next prime is 261800093. The reversal of 261800087 is 780008162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261800087 - 2²⁴ = 245022871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261800057) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88637 + ... + 91542.

It is an arithmetic number, because the mean of its divisors is an integer number (65495430).

Almost surely, 2^261800087 is an apocalyptic number.

261800087 is a deficient number, since it is larger than the sum of its proper divisors (181633).

261800087 is a wasteful number, since it uses less digits than its factorization.

261800087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181632.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 261800087 is about 16180.2375446098. The cubic root of 261800087 is about 639.7200004023.

The spelling of 261800087 in words is "two hundred sixty-one million, eight hundred thousand, eighty-seven".