261915 has 16 divisors (see below), whose sum is σ = 441600. Its totient is φ = 132192.

The previous prime is 261887. The next prime is 261917. The reversal of 261915 is 519162.

It is not a de Polignac number, because 261915 - 2⁷ = 261787 is a prime.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (261917) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175 + ... + 744.

It is an arithmetic number, because the mean of its divisors is an integer number (27600).

2²⁶¹⁹¹⁵ is an apocalyptic number.

261915 is a deficient number, since it is larger than the sum of its proper divisors (179685).

261915 is a wasteful number, since it uses less digits than its factorization.

261915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946.

The product of its digits is 540, while the sum is 24.

The square root of 261915 is about 511.7763183267. The cubic root of 261915 is about 63.9813585030.

It can be divided in two parts, 261 and 915, that added together give a triangular number (1176 = T₄₈).

The spelling of 261915 in words is "two hundred sixty-one thousand, nine hundred fifteen".