1661383775056 has 40 divisors (see below), whose sum is σ = 3241414114344. Its totient is φ = 824909998080.

The previous prime is 1661383775033. The next prime is 1661383775321. The reversal of 1661383775056 is 6505773831661.

It can be written as a sum of positive squares in 4 ways, for example, as 484115374656 + 1177268400400 = 695784^2 + 1085020^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 686740 + ... + 1947916.

Almost surely, 2^{1661383775056} is an apocalyptic number.

1661383775056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1661383775056 is a deficient number, since it is larger than the sum of its proper divisors (1580030339288).

1661383775056 is a wasteful number, since it uses less digits than its factorization.

1661383775056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1261759 (or 1261753 counting only the distinct ones).

The product of its (nonzero) digits is 19051200, while the sum is 58.

The spelling of 1661383775056 in words is "one trillion, six hundred sixty-one billion, three hundred eighty-three million, seven hundred seventy-five thousand, fifty-six".