551520021 has 32 divisors (see below), whose sum is σ = 815455872. Its totient is φ = 329414400.

The previous prime is 551520017. The next prime is 551520031. The reversal of 551520021 is 120025155.

551520021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 551520021 - 2² = 551520017 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 551520021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551520031) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 289171 + ... + 291071.

It is an arithmetic number, because the mean of its divisors is an integer number (25482996).

Almost surely, 2^551520021 is an apocalyptic number.

It is an amenable number.

551520021 is a deficient number, since it is larger than the sum of its proper divisors (263935851).

551520021 is a wasteful number, since it uses less digits than its factorization.

551520021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2133.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 551520021 is about 23484.4633960412. The cubic root of 551520021 is about 820.0753554584.

Adding to 551520021 its reverse (120025155), we get a palindrome (671545176).

The spelling of 551520021 in words is "five hundred fifty-one million, five hundred twenty thousand, twenty-one".