261643613466 has 8 divisors (see below), whose sum is σ = 523287226944. Its totient is φ = 87214537820.

The previous prime is 261643613461. The next prime is 261643613477. The reversal of 261643613466 is 664316346162.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

261643613466 is an admirable number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261643613461) 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, 21803634450 + ... + 21803634461.

It is an arithmetic number, because the mean of its divisors is an integer number (65410903368).

Almost surely, 2^261643613466 is an apocalyptic number.

261643613466 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261643613466 is a wasteful number, since it uses less digits than its factorization.

261643613466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43607268916.

The product of its digits is 2239488, while the sum is 48.

The spelling of 261643613466 in words is "two hundred sixty-one billion, six hundred forty-three million, six hundred thirteen thousand, four hundred sixty-six".