261550 has 12 divisors (see below), whose sum is σ = 486576. Its totient is φ = 104600.

The previous prime is 261529. The next prime is 261557. The reversal of 261550 is 55162.

It is a happy number.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261557) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2566 + ... + 2665.

It is an arithmetic number, because the mean of its divisors is an integer number (40548).

2²⁶¹⁵⁵⁰ is an apocalyptic number.

261550 is a deficient number, since it is larger than the sum of its proper divisors (225026).

261550 is a wasteful number, since it uses less digits than its factorization.

261550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5243 (or 5238 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 261550 is about 511.4195928980. The cubic root of 261550 is about 63.9516235986.

The spelling of 261550 in words is "two hundred sixty-one thousand, five hundred fifty".