261001056 has 96 divisors (see below), whose sum is σ = 731808000. Its totient is φ = 81252864.

The previous prime is 261001007. The next prime is 261001067. The reversal of 261001056 is 650100162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-3 number, since 3×261001056³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93570 + ... + 96318.

It is an arithmetic number, because the mean of its divisors is an integer number (7623000).

Almost surely, 2^261001056 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 261001056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (365904000).

261001056 is an abundant number, since it is smaller than the sum of its proper divisors (470806944).

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

261001056 is a wasteful number, since it uses less digits than its factorization.

261001056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2828 (or 2820 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 261001056 is about 16155.5271037500. The cubic root of 261001056 is about 639.0685147231.

It can be divided in two parts, 26100 and 1056, that multiplied together give a triangular number (27561600 = T₇₄₂₄).

The spelling of 261001056 in words is "two hundred sixty-one million, one thousand, fifty-six".