55281621 has 16 divisors (see below), whose sum is σ = 77760000. Its totient is φ = 34837488.

The previous prime is 55281619. The next prime is 55281641. The reversal of 55281621 is 12618255.

It is not a de Polignac number, because 55281621 - 2¹ = 55281619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55281641) 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, 36130 + ... + 37628.

It is an arithmetic number, because the mean of its divisors is an integer number (4860000).

Almost surely, 2^55281621 is an apocalyptic number.

It is an amenable number.

55281621 is a deficient number, since it is larger than the sum of its proper divisors (22478379).

55281621 is a wasteful number, since it uses less digits than its factorization.

55281621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2168.

The product of its digits is 4800, while the sum is 30.

The square root of 55281621 is about 7435.1611280456. The cubic root of 55281621 is about 380.9432269827.

Adding to 55281621 its reverse (12618255), we get a palindrome (67899876).

The spelling of 55281621 in words is "fifty-five million, two hundred eighty-one thousand, six hundred twenty-one".