261501 has 8 divisors (see below), whose sum is σ = 354144. Its totient is φ = 171600.

The previous prime is 261467. The next prime is 261509. The reversal of 261501 is 105162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261501 - 2¹¹ = 259453 is a prime.

261501 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 450 + ... + 851.

It is an arithmetic number, because the mean of its divisors is an integer number (44268).

2²⁶¹⁵⁰¹ is an apocalyptic number.

It is an amenable number.

261501 is a deficient number, since it is larger than the sum of its proper divisors (92643).

261501 is a wasteful number, since it uses less digits than its factorization.

261501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1371.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 261501 is about 511.3716847851. The cubic root of 261501 is about 63.9476296838.

Adding to 261501 its reverse (105162), we get a palindrome (366663).

The spelling of 261501 in words is "two hundred sixty-one thousand, five hundred one".