261570 has 16 divisors (see below), whose sum is σ = 627840. Its totient is φ = 69744.

The previous prime is 261563. The next prime is 261577. The reversal of 261570 is 75162.

It is an interprime number because it is at equal distance from previous prime (261563) and next prime (261577).

It is not an unprimeable number, because it can be changed into a prime (261577) by changing a digit.

261570 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4330 + ... + 4389.

It is an arithmetic number, because the mean of its divisors is an integer number (39240).

2²⁶¹⁵⁷⁰ is an apocalyptic number.

261570 is an abundant number, since it is smaller than the sum of its proper divisors (366270).

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

261570 is a wasteful number, since it uses less digits than its factorization.

261570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8729.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 261570 is about 511.4391459402. The cubic root of 261570 is about 63.9532536246.

It can be divided in two parts, 26 and 1570, that added together give a triangular number (1596 = T₅₆).

The spelling of 261570 in words is "two hundred sixty-one thousand, five hundred seventy".