261115121 has 4 divisors (see below), whose sum is σ = 276474852. Its totient is φ = 245755392.

The previous prime is 261115109. The next prime is 261115163. The reversal of 261115121 is 121511162.

261115121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 155251600 + 105863521 = 12460^2 + 10289^2 .

It is a cyclic number.

It is not a de Polignac number, because 261115121 - 2²² = 256920817 is a prime.

It is a super-2 number, since 2×261115121² = 136362212829689282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261115093 and 261115102.

It is not an unprimeable number, because it can be changed into a prime (261115171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7679840 + ... + 7679873.

It is an arithmetic number, because the mean of its divisors is an integer number (69118713).

Almost surely, 2^261115121 is an apocalyptic number.

It is an amenable number.

261115121 is a deficient number, since it is larger than the sum of its proper divisors (15359731).

261115121 is a wasteful number, since it uses less digits than its factorization.

261115121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15359730.

The product of its digits is 120, while the sum is 20.

The square root of 261115121 is about 16159.0569341159. The cubic root of 261115121 is about 639.1615982974.

Adding to 261115121 its reverse (121511162), we get a palindrome (382626283).

The spelling of 261115121 in words is "two hundred sixty-one million, one hundred fifteen thousand, one hundred twenty-one".