55131621 has 16 divisors (see below), whose sum is σ = 77070336. Its totient is φ = 34988976.

The previous prime is 55131563. The next prime is 55131623. The reversal of 55131621 is 12613155.

It is not a de Polignac number, because 55131621 - 2¹³ = 55123429 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 55131591 and 55131600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55131623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13596 + ... + 17178.

It is an arithmetic number, because the mean of its divisors is an integer number (4816896).

Almost surely, 2^55131621 is an apocalyptic number.

It is an amenable number.

55131621 is a deficient number, since it is larger than the sum of its proper divisors (21938715).

55131621 is a wasteful number, since it uses less digits than its factorization.

55131621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3832.

The product of its digits is 900, while the sum is 24.

The square root of 55131621 is about 7425.0670704041. The cubic root of 55131621 is about 380.5983670742.

Adding to 55131621 its reverse (12613155), we get a palindrome (67744776).

The spelling of 55131621 in words is "fifty-five million, one hundred thirty-one thousand, six hundred twenty-one".