55530421 has 2 divisors, whose sum is σ = 55530422. Its totient is φ = 55530420.

The previous prime is 55530413. The next prime is 55530473. The reversal of 55530421 is 12403555.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49210225 + 6320196 = 7015^2 + 2514^2 .

It is a cyclic number.

It is not a de Polignac number, because 55530421 - 2³ = 55530413 is a prime.

It is equal to p_3311935 and since 55530421 and 3311935 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55530481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27765210 + 27765211.

It is an arithmetic number, because the mean of its divisors is an integer number (27765211).

Almost surely, 2^55530421 is an apocalyptic number.

It is an amenable number.

55530421 is a deficient number, since it is larger than the sum of its proper divisors (1).

55530421 is an equidigital number, since it uses as much as digits as its factorization.

55530421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 55530421 is about 7451.8736570073. The cubic root of 55530421 is about 381.5138617368.

Adding to 55530421 its reverse (12403555), we get a palindrome (67933976).

It can be divided in two parts, 555 and 30421, that added together give a square (30976 = 176²).

The spelling of 55530421 in words is "fifty-five million, five hundred thirty thousand, four hundred twenty-one".