55559259821 has 4 divisors (see below), whose sum is σ = 59833049052. Its totient is φ = 51285470592.

The previous prime is 55559259727. The next prime is 55559259827. The reversal of 55559259821 is 12895295555.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 28774336900 + 26784922921 = 169630^2 + 163661^2 .

It is a cyclic number.

It is not a de Polignac number, because 55559259821 - 2¹⁸ = 55558997677 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 (55559259827) 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, 2136894596 + ... + 2136894621.

It is an arithmetic number, because the mean of its divisors is an integer number (14958262263).

Almost surely, 2^55559259821 is an apocalyptic number.

It is an amenable number.

55559259821 is a deficient number, since it is larger than the sum of its proper divisors (4273789231).

55559259821 is a wasteful number, since it uses less digits than its factorization.

55559259821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4273789230.

The product of its digits is 8100000, while the sum is 56.

The spelling of 55559259821 in words is "fifty-five billion, five hundred fifty-nine million, two hundred fifty-nine thousand, eight hundred twenty-one".