55185821 has 4 divisors (see below), whose sum is σ = 55474944. Its totient is φ = 54896700.

The previous prime is 55185803. The next prime is 55185847. The reversal of 55185821 is 12858155.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55185821 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 (55185881) 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, 144275 + ... + 144656.

It is an arithmetic number, because the mean of its divisors is an integer number (13868736).

Almost surely, 2^55185821 is an apocalyptic number.

It is an amenable number.

55185821 is a deficient number, since it is larger than the sum of its proper divisors (289123).

55185821 is a wasteful number, since it uses less digits than its factorization.

55185821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289122.

The product of its digits is 16000, while the sum is 35.

The square root of 55185821 is about 7428.7159724948. The cubic root of 55185821 is about 380.7230485478.

The spelling of 55185821 in words is "fifty-five million, one hundred eighty-five thousand, eight hundred twenty-one".