261642 has 8 divisors (see below), whose sum is σ = 523296. Its totient is φ = 87212.

The previous prime is 261641. The next prime is 261643. The reversal of 261642 is 246162.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (261641) and next prime (261643).

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

261642 is an admirable number.

It is a super-3 number, since 3×261642³ = 53733315105063864, which contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (261641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21798 + ... + 21809.

It is an arithmetic number, because the mean of its divisors is an integer number (65412).

2²⁶¹⁶⁴² is an apocalyptic number.

261642 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

261642 is a wasteful number, since it uses less digits than its factorization.

261642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43612.

The product of its digits is 576, while the sum is 21.

The square root of 261642 is about 511.5095307030. The cubic root of 261642 is about 63.9591210302.

It can be divided in two parts, 261 and 642, that added together give a triangular number (903 = T₄₂).

The spelling of 261642 in words is "two hundred sixty-one thousand, six hundred forty-two".