261148667061657 has 4 divisors (see below), whose sum is σ = 348198222748880. Its totient is φ = 174099111374436.

The previous prime is 261148667061613. The next prime is 261148667061677. The reversal of 261148667061657 is 756160766841162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-261148667061657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261148667061677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43524777843607 + ... + 43524777843612.

It is an arithmetic number, because the mean of its divisors is an integer number (87049555687220).

Almost surely, 2^{261148667061657} is an apocalyptic number.

It is an amenable number.

261148667061657 is a deficient number, since it is larger than the sum of its proper divisors (87049555687223).

261148667061657 is an equidigital number, since it uses as much as digits as its factorization.

261148667061657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87049555687222.

The product of its (nonzero) digits is 121927680, while the sum is 66.

The spelling of 261148667061657 in words is "two hundred sixty-one trillion, one hundred forty-eight billion, six hundred sixty-seven million, sixty-one thousand, six hundred fifty-seven".