55821131 has 4 divisors (see below), whose sum is σ = 57182664. Its totient is φ = 54459600.

The previous prime is 55821127. The next prime is 55821169. The reversal of 55821131 is 13112855.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 55821131 - 2² = 55821127 is a prime.

It is a super-2 number, since 2×55821131² = 6231997332238322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55821131.

It is not an unprimeable number, because it can be changed into a prime (55821191) 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, 680705 + ... + 680786.

It is an arithmetic number, because the mean of its divisors is an integer number (14295666).

Almost surely, 2^55821131 is an apocalyptic number.

55821131 is a deficient number, since it is larger than the sum of its proper divisors (1361533).

55821131 is a wasteful number, since it uses less digits than its factorization.

55821131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361532.

The product of its digits is 1200, while the sum is 26.

The square root of 55821131 is about 7471.3540272162. The cubic root of 55821131 is about 382.1784638920.

Adding to 55821131 its reverse (13112855), we get a palindrome (68933986).

The spelling of 55821131 in words is "fifty-five million, eight hundred twenty-one thousand, one hundred thirty-one".