55120621 has 4 divisors (see below), whose sum is σ = 55875772. Its totient is φ = 54365472.

The previous prime is 55120601. The next prime is 55120631. The reversal of 55120621 is 12602155.

55120621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12602155 = 5 ⋅2520431.

It can be written as a sum of positive squares in 2 ways, for example, as 34644996 + 20475625 = 5886^2 + 4525^2 .

It is a cyclic number.

It is not a de Polignac number, because 55120621 - 2²⁵ = 21566189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55120592 and 55120601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55120601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 377466 + ... + 377611.

It is an arithmetic number, because the mean of its divisors is an integer number (13968943).

Almost surely, 2^55120621 is an apocalyptic number.

It is an amenable number.

55120621 is a deficient number, since it is larger than the sum of its proper divisors (755151).

55120621 is an equidigital number, since it uses as much as digits as its factorization.

55120621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 755150.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 55120621 is about 7424.3262994025. The cubic root of 55120621 is about 380.5730527420.

Adding to 55120621 its reverse (12602155), we get a palindrome (67722776).

The spelling of 55120621 in words is "fifty-five million, one hundred twenty thousand, six hundred twenty-one".