551504321 has 4 divisors (see below), whose sum is σ = 551555412. Its totient is φ = 551453232.

The previous prime is 551504311. The next prime is 551504377. The reversal of 551504321 is 123405155.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 123405155 = 5 ⋅24681031.

It can be written as a sum of positive squares in 2 ways, for example, as 41422096 + 510082225 = 6436^2 + 22585^2 .

It is a cyclic number.

It is not a de Polignac number, because 551504321 - 2⁶ = 551504257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551504311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2306 + ... + 33291.

It is an arithmetic number, because the mean of its divisors is an integer number (137888853).

Almost surely, 2^551504321 is an apocalyptic number.

It is an amenable number.

551504321 is a deficient number, since it is larger than the sum of its proper divisors (51091).

551504321 is a wasteful number, since it uses less digits than its factorization.

551504321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51090.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 551504321 is about 23484.1291301168. The cubic root of 551504321 is about 820.0675737492.

Adding to 551504321 its reverse (123405155), we get a palindrome (674909476).

The spelling of 551504321 in words is "five hundred fifty-one million, five hundred four thousand, three hundred twenty-one".