261333505 has 16 divisors (see below), whose sum is σ = 330549120. Its totient is φ = 197797248.

The previous prime is 261333497. The next prime is 261333511. The reversal of 261333505 is 505333162.

It is a cyclic number.

It is not a de Polignac number, because 261333505 - 2³ = 261333497 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96804 + ... + 99466.

It is an arithmetic number, because the mean of its divisors is an integer number (20659320).

Almost surely, 2^261333505 is an apocalyptic number.

It is an amenable number.

261333505 is a deficient number, since it is larger than the sum of its proper divisors (69215615).

261333505 is a wasteful number, since it uses less digits than its factorization.

261333505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3720.

The product of its (nonzero) digits is 8100, while the sum is 28.

The square root of 261333505 is about 16165.8128468692. The cubic root of 261333505 is about 639.3397365462.

Adding to 261333505 its reverse (505333162), we get a palindrome (766666667).

The spelling of 261333505 in words is "two hundred sixty-one million, three hundred thirty-three thousand, five hundred five".