55645621 has 2 divisors, whose sum is σ = 55645622. Its totient is φ = 55645620.

The previous prime is 55645591. The next prime is 55645633. The reversal of 55645621 is 12654655.

55645621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45495025 + 10150596 = 6745^2 + 3186^2 .

It is a cyclic number.

It is not a de Polignac number, because 55645621 - 2⁷ = 55645493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55645021) 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 as a sum of consecutive naturals, namely, 27822810 + 27822811.

It is an arithmetic number, because the mean of its divisors is an integer number (27822811).

Almost surely, 2^55645621 is an apocalyptic number.

It is an amenable number.

55645621 is a deficient number, since it is larger than the sum of its proper divisors (1).

55645621 is an equidigital number, since it uses as much as digits as its factorization.

55645621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36000, while the sum is 34.

The square root of 55645621 is about 7459.5992519706. The cubic root of 55645621 is about 381.7775012506. Note that the first 3 decimals are identical.

The spelling of 55645621 in words is "fifty-five million, six hundred forty-five thousand, six hundred twenty-one".