261240250605 has 16 divisors (see below), whose sum is σ = 442571719104. Its totient is φ = 131132360960.

The previous prime is 261240250603. The next prime is 261240250619. The reversal of 261240250605 is 506052042162.

It is not a de Polignac number, because 261240250605 - 2¹ = 261240250603 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261240250603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 512235531 + ... + 512236040.

It is an arithmetic number, because the mean of its divisors is an integer number (27660732444).

Almost surely, 2^261240250605 is an apocalyptic number.

It is an amenable number.

261240250605 is a deficient number, since it is larger than the sum of its proper divisors (181331468499).

261240250605 is a wasteful number, since it uses less digits than its factorization.

261240250605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024471596.

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 261240250605 its reverse (506052042162), we get a palindrome (767292292767).

The spelling of 261240250605 in words is "two hundred sixty-one billion, two hundred forty million, two hundred fifty thousand, six hundred five".