55407321 has 20 divisors (see below), whose sum is σ = 83389812. Its totient is φ = 36661248.

The previous prime is 55407311. The next prime is 55407329. The reversal of 55407321 is 12370455.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 25857225 + 29550096 = 5085^2 + 5436^2 .

It is not a de Polignac number, because 55407321 - 2⁶ = 55407257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55407329) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8601 + ... + 13593.

Almost surely, 2^55407321 is an apocalyptic number.

It is an amenable number.

55407321 is a deficient number, since it is larger than the sum of its proper divisors (27982491).

55407321 is a wasteful number, since it uses less digits than its factorization.

55407321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5142 (or 5133 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 55407321 is about 7443.6094067327. The cubic root of 55407321 is about 381.2317394819.

Adding to 55407321 its reverse (12370455), we get a palindrome (67777776).

The spelling of 55407321 in words is "fifty-five million, four hundred seven thousand, three hundred twenty-one".