55401661791 has 18 divisors (see below), whose sum is σ = 93089867832. Its totient is φ = 31658092200.

The previous prime is 55401661789. The next prime is 55401661801. The reversal of 55401661791 is 19716610455.

55401661791 is a `hidden beast` number, since 5 + 540 + 1 + 6 + 6 + 17 + 91 = 666.

It is not a de Polignac number, because 55401661791 - 2¹ = 55401661789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55401661751) 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 17 ways as a sum of consecutive naturals, for example, 62813235 + ... + 62814116.

It is an arithmetic number, because the mean of its divisors is an integer number (5171659324).

Almost surely, 2^55401661791 is an apocalyptic number.

55401661791 is a deficient number, since it is larger than the sum of its proper divisors (37688206041).

55401661791 is a wasteful number, since it uses less digits than its factorization.

55401661791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125627371 (or 125627361 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The spelling of 55401661791 in words is "fifty-five billion, four hundred one million, six hundred sixty-one thousand, seven hundred ninety-one".