261351611 has 4 divisors (see below), whose sum is σ = 261429000. Its totient is φ = 261274224.

The previous prime is 261351583. The next prime is 261351617. The reversal of 261351611 is 116153162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 116153162 = 2 ⋅58076581.

It is a cyclic number.

It is not a de Polignac number, because 261351611 - 2¹⁴ = 261335227 is a prime.

It is a super-3 number, since 3×261351611³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261351617) 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, 33386 + ... + 40463.

It is an arithmetic number, because the mean of its divisors is an integer number (65357250).

Almost surely, 2^261351611 is an apocalyptic number.

261351611 is a deficient number, since it is larger than the sum of its proper divisors (77389).

261351611 is an equidigital number, since it uses as much as digits as its factorization.

261351611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77388.

The product of its digits is 1080, while the sum is 26.

The square root of 261351611 is about 16166.3728461272. The cubic root of 261351611 is about 639.3545013553.

The spelling of 261351611 in words is "two hundred sixty-one million, three hundred fifty-one thousand, six hundred eleven".