55982821 has 4 divisors (see below), whose sum is σ = 56058912. Its totient is φ = 55906732.

The previous prime is 55982809. The next prime is 55982827. The reversal of 55982821 is 12828955.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12828955 = 5 ⋅2565791.

It is a cyclic number.

It is not a de Polignac number, because 55982821 - 2²¹ = 53885669 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55982827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36931 + ... + 38416.

It is an arithmetic number, because the mean of its divisors is an integer number (14014728).

Almost surely, 2^55982821 is an apocalyptic number.

It is an amenable number.

55982821 is a deficient number, since it is larger than the sum of its proper divisors (76091).

55982821 is an equidigital number, since it uses as much as digits as its factorization.

55982821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76090.

The product of its digits is 57600, while the sum is 40.

The square root of 55982821 is about 7482.1668652871. The cubic root of 55982821 is about 382.5471108334.

The spelling of 55982821 in words is "fifty-five million, nine hundred eighty-two thousand, eight hundred twenty-one".