261421722045056 has 16 divisors (see below), whose sum is σ = 520801086886890. Its totient is φ = 130710861022464.

The previous prime is 261421722045017. The next prime is 261421722045059. The reversal of 261421722045056 is 650540227124162.

It can be written as a sum of positive squares in only one way, i.e., 143889237307456 + 117532484737600 = 11995384^2 + 10841240^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a self number, because there is not a number n which added to its sum of digits gives 261421722045056.

It is not an unprimeable number, because it can be changed into a prime (261421722045059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1021178601611 + ... + 1021178601866.

Almost surely, 2^{261421722045056} is an apocalyptic number.

It is an amenable number.

261421722045056 is a deficient number, since it is larger than the sum of its proper divisors (259379364841834).

261421722045056 is an equidigital number, since it uses as much as digits as its factorization.

261421722045056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2042357203491 (or 2042357203479 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 47.

The spelling of 261421722045056 in words is "two hundred sixty-one trillion, four hundred twenty-one billion, seven hundred twenty-two million, forty-five thousand, fifty-six".