261321271 has 4 divisors (see below), whose sum is σ = 262315152. Its totient is φ = 260327392.

The previous prime is 261321259. The next prime is 261321299. The reversal of 261321271 is 172123162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 172123162 = 2 ⋅86061581.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261321271 is a prime.

It is a super-4 number, since 4×261321271⁴ (a number of 35 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261321211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496546 + ... + 497071.

It is an arithmetic number, because the mean of its divisors is an integer number (65578788).

Almost surely, 2^261321271 is an apocalyptic number.

261321271 is a deficient number, since it is larger than the sum of its proper divisors (993881).

261321271 is an equidigital number, since it uses as much as digits as its factorization.

261321271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993880.

The product of its digits is 1008, while the sum is 25.

The square root of 261321271 is about 16165.4344513224. The cubic root of 261321271 is about 639.3297597615.

The spelling of 261321271 in words is "two hundred sixty-one million, three hundred twenty-one thousand, two hundred seventy-one".