261972 has 36 divisors (see below), whose sum is σ = 698880. Its totient is φ = 82512.

The previous prime is 261971. The next prime is 261973. The reversal of 261972 is 279162.

It is an interprime number because it is at equal distance from previous prime (261971) and next prime (261973).

It is a tau number, because it is divible by the number of its divisors (36).

It is a nialpdrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261971) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 493 + ... + 875.

261972 is a Friedman number, since it can be written as (6-2)^9-172, using all its digits and the basic arithmetic operations.

2²⁶¹⁹⁷² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (349440).

261972 is an abundant number, since it is smaller than the sum of its proper divisors (436908).

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

261972 is a wasteful number, since it uses less digits than its factorization.

261972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 407 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 261972 is about 511.8320036887. The cubic root of 261972 is about 63.9859995417.

The spelling of 261972 in words is "two hundred sixty-one thousand, nine hundred seventy-two".