261356405604461 has 4 divisors (see below), whose sum is σ = 261643295183424. Its totient is φ = 261069516025500.

The previous prime is 261356405604439. The next prime is 261356405604521. The reversal of 261356405604461 is 164406504653162.

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 cyclic number.

It is not a de Polignac number, because 261356405604461 - 2²² = 261356401410157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261356405604061) 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, 143444788115 + ... + 143444789936.

It is an arithmetic number, because the mean of its divisors is an integer number (65410823795856).

Almost surely, 2^{261356405604461} is an apocalyptic number.

It is an amenable number.

261356405604461 is a deficient number, since it is larger than the sum of its proper divisors (286889578963).

261356405604461 is an equidigital number, since it uses as much as digits as its factorization.

261356405604461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286889578962.

The product of its (nonzero) digits is 12441600, while the sum is 53.

The spelling of 261356405604461 in words is "two hundred sixty-one trillion, three hundred fifty-six billion, four hundred five million, six hundred four thousand, four hundred sixty-one".