55821821 has 8 divisors (see below), whose sum is σ = 61286304. Its totient is φ = 50422320.

The previous prime is 55821811. The next prime is 55821877. The reversal of 55821821 is 12812855.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55821821 - 2⁶ = 55821757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55821811) 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 7 ways as a sum of consecutive naturals, for example, 14435 + ... + 17888.

It is an arithmetic number, because the mean of its divisors is an integer number (7660788).

Almost surely, 2^55821821 is an apocalyptic number.

It is an amenable number.

55821821 is a deficient number, since it is larger than the sum of its proper divisors (5464483).

55821821 is a wasteful number, since it uses less digits than its factorization.

55821821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32491.

The product of its digits is 6400, while the sum is 32.

The square root of 55821821 is about 7471.4002034425. The cubic root of 55821821 is about 382.1800385768.

The spelling of 55821821 in words is "fifty-five million, eight hundred twenty-one thousand, eight hundred twenty-one".