1605551573761 has 4 divisors (see below), whose sum is σ = 1617270928452. Its totient is φ = 1593832219072.

The previous prime is 1605551573753. The next prime is 1605551573779. The reversal of 1605551573761 is 1673751555061.

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 719920007361 + 885631566400 = 848481^2 + 941080^2 .

It is a cyclic number.

It is not a de Polignac number, because 1605551573761 - 2³ = 1605551573753 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1605551573699 and 1605551573708.

It is not an unprimeable number, because it can be changed into a prime (1605551573711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5859677140 + ... + 5859677413.

It is an arithmetic number, because the mean of its divisors is an integer number (404317732113).

Almost surely, 2^{1605551573761} is an apocalyptic number.

It is an amenable number.

1605551573761 is a deficient number, since it is larger than the sum of its proper divisors (11719354691).

1605551573761 is a wasteful number, since it uses less digits than its factorization.

1605551573761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11719354690.

The product of its (nonzero) digits is 3307500, while the sum is 52.

The spelling of 1605551573761 in words is "one trillion, six hundred five billion, five hundred fifty-one million, five hundred seventy-three thousand, seven hundred sixty-one".