261090 has 32 divisors (see below), whose sum is σ = 696960. Its totient is φ = 69552.

The previous prime is 261089. The next prime is 261101. The reversal of 261090 is 90162.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 214 + ... + 753.

It is an arithmetic number, because the mean of its divisors is an integer number (21780).

2²⁶¹⁰⁹⁰ is an apocalyptic number.

261090 is an abundant number, since it is smaller than the sum of its proper divisors (435870).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261090 is a wasteful number, since it uses less digits than its factorization.

261090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983 (or 977 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 261090 is about 510.9696664187. The cubic root of 261090 is about 63.9141100450.

The spelling of 261090 in words is "two hundred sixty-one thousand, ninety".