261056405 has 8 divisors (see below), whose sum is σ = 324070200. Its totient is φ = 201643456.

The previous prime is 261056401. The next prime is 261056413. The reversal of 261056405 is 504650162.

It can be written as a sum of positive squares in 4 ways, for example, as 39225169 + 221831236 = 6263^2 + 14894^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 261056405 - 2² = 261056401 is a prime.

It is a super-3 number, since 3×261056405³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261056401) 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, 900050 + ... + 900339.

It is an arithmetic number, because the mean of its divisors is an integer number (40508775).

Almost surely, 2^261056405 is an apocalyptic number.

It is an amenable number.

261056405 is a deficient number, since it is larger than the sum of its proper divisors (63013795).

261056405 is a wasteful number, since it uses less digits than its factorization.

261056405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1800423.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 261056405 is about 16157.2400180229. The cubic root of 261056405 is about 639.1136860642.

The spelling of 261056405 in words is "two hundred sixty-one million, fifty-six thousand, four hundred five".