55819891 has 16 divisors (see below), whose sum is σ = 63676800. Its totient is φ = 48601728.

The previous prime is 55819889. The next prime is 55819913. The reversal of 55819891 is 19891855.

It is a cyclic number.

It is not a de Polignac number, because 55819891 - 2¹ = 55819889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55819811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11880 + ... + 15898.

It is an arithmetic number, because the mean of its divisors is an integer number (3979800).

Almost surely, 2^55819891 is an apocalyptic number.

55819891 is a deficient number, since it is larger than the sum of its proper divisors (7856909).

55819891 is a wasteful number, since it uses less digits than its factorization.

55819891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4098.

The product of its digits is 129600, while the sum is 46.

The square root of 55819891 is about 7471.2710431358. The cubic root of 55819891 is about 382.1756339912.

Subtracting from 55819891 its reverse (19891855), we obtain a square (35928036 = 5994²).

It can be divided in two parts, 558 and 19891, that added together give a square (20449 = 143²).

The spelling of 55819891 in words is "fifty-five million, eight hundred nineteen thousand, eight hundred ninety-one".