261113281 has 27 divisors (see below), whose sum is σ = 313559337. Its totient is φ = 217176960.

The previous prime is 261113267. The next prime is 261113317. The reversal of 261113281 is 182311162.

The square root of 261113281 is 16159.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 194853681 + 66259600 = 13959^2 + 8140^2 .

It is not a de Polignac number, because 261113281 - 2⁹ = 261112769 is a prime.

It is a super-2 number, since 2×261113281² = 136360291029169922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261113201) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2310681 + ... + 2310793.

Almost surely, 2^261113281 is an apocalyptic number.

261113281 is the 16159-th square number.

261113281 is the 8080-th centered octagonal number.

It is an amenable number.

261113281 is a deficient number, since it is larger than the sum of its proper divisors (52446056).

261113281 is a wasteful number, since it uses less digits than its factorization.

261113281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 137 counting only the distinct ones).

The product of its digits is 576, while the sum is 25.

The cubic root of 261113281 is about 639.1600969672.

Multiplying 261113281 by its sum of digits (25), we get a square (6527832025 = 80795²).

Multiplying 261113281 by its product of digits (576), we get a square (150401249856 = 387816²).

It can be divided in two parts, 26111 and 3281, that added together give a palindrome (29392).

The spelling of 261113281 in words is "two hundred sixty-one million, one hundred thirteen thousand, two hundred eighty-one".