261523705 has 4 divisors (see below), whose sum is σ = 313828452. Its totient is φ = 209218960.

The previous prime is 261523693. The next prime is 261523709. The reversal of 261523705 is 507325162.

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 38588944 + 222934761 = 6212^2 + 14931^2 .

It is not a de Polignac number, because 261523705 - 2⁵ = 261523673 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261523709) 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, 26152366 + ... + 26152375.

It is an arithmetic number, because the mean of its divisors is an integer number (78457113).

Almost surely, 2^261523705 is an apocalyptic number.

It is an amenable number.

261523705 is a deficient number, since it is larger than the sum of its proper divisors (52304747).

261523705 is an equidigital number, since it uses as much as digits as its factorization.

261523705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52304746.

The product of its (nonzero) digits is 12600, while the sum is 31.

The square root of 261523705 is about 16171.6945617953. The cubic root of 261523705 is about 639.4948039556.

Adding to 261523705 its reverse (507325162), we get a palindrome (768848867).

The spelling of 261523705 in words is "two hundred sixty-one million, five hundred twenty-three thousand, seven hundred five".