551804021 has 8 divisors (see below), whose sum is σ = 555555000. Its totient is φ = 548061120.

The previous prime is 551803991. The next prime is 551804039. The reversal of 551804021 is 120408155.

It can be written as a sum of positive squares in 4 ways, for example, as 123520996 + 428283025 = 11114^2 + 20695^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 551804021 - 2⁶ = 551803957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551804321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199355 + ... + 202103.

It is an arithmetic number, because the mean of its divisors is an integer number (69444375).

Almost surely, 2^551804021 is an apocalyptic number.

It is an amenable number.

551804021 is a deficient number, since it is larger than the sum of its proper divisors (3750979).

551804021 is a wasteful number, since it uses less digits than its factorization.

551804021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4039.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 551804021 is about 23490.5091685983. The cubic root of 551804021 is about 820.2160946438.

The spelling of 551804021 in words is "five hundred fifty-one million, eight hundred four thousand, twenty-one".