261335011537 has 4 divisors (see below), whose sum is σ = 265619192116. Its totient is φ = 257050830960.

The previous prime is 261335011523. The next prime is 261335011543. The reversal of 261335011537 is 735110533162.

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 105676356241 + 155658655296 = 325079^2 + 394536^2 .

It is a cyclic number.

It is not a de Polignac number, because 261335011537 - 2¹⁵ = 261334978769 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261335011496 and 261335011505.

It is not an unprimeable number, because it can be changed into a prime (261335012537) 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, 2142090198 + ... + 2142090319.

It is an arithmetic number, because the mean of its divisors is an integer number (66404798029).

Almost surely, 2^261335011537 is an apocalyptic number.

It is an amenable number.

261335011537 is a deficient number, since it is larger than the sum of its proper divisors (4284180579).

261335011537 is an equidigital number, since it uses as much as digits as its factorization.

261335011537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4284180578.

The product of its (nonzero) digits is 56700, while the sum is 37.

Adding to 261335011537 its reverse (735110533162), we get a palindrome (996445544699).

The spelling of 261335011537 in words is "two hundred sixty-one billion, three hundred thirty-five million, eleven thousand, five hundred thirty-seven".