551521 has 4 divisors (see below), whose sum is σ = 569344. Its totient is φ = 533700.

The previous prime is 551519. The next prime is 551539. The reversal of 551521 is 125155.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 125155 = 5 ⋅25031.

It is a cyclic number.

It is not a de Polignac number, because 551521 - 2¹ = 551519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551581) 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, 8865 + ... + 8926.

It is an arithmetic number, because the mean of its divisors is an integer number (142336).

2⁵⁵¹⁵²¹ is an apocalyptic number.

It is an amenable number.

551521 is a deficient number, since it is larger than the sum of its proper divisors (17823).

551521 is a wasteful number, since it uses less digits than its factorization.

551521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17822.

The product of its digits is 250, while the sum is 19.

The square root of 551521 is about 742.6445987146. The cubic root of 551521 is about 82.0075840695.

Adding to 551521 its reverse (125155), we get a palindrome (676676).

The spelling of 551521 in words is "five hundred fifty-one thousand, five hundred twenty-one".