551811816 has 24 divisors (see below), whose sum is σ = 1494490530. Its totient is φ = 183937248.

The previous prime is 551811809. The next prime is 551811829. The reversal of 551811816 is 618118155.

551811816 is a `hidden beast` number, since 551 + 81 + 18 + 16 = 666.

It can be written as a sum of positive squares in only one way, i.e., 540562500 + 11249316 = 23250^2 + 3354^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3831955 + ... + 3832098.

Almost surely, 2^551811816 is an apocalyptic number.

It is an amenable number.

551811816 is an abundant number, since it is smaller than the sum of its proper divisors (942678714).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

551811816 is a wasteful number, since it uses less digits than its factorization.

551811816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7664065 (or 7664058 counting only the distinct ones).

The product of its digits is 9600, while the sum is 36.

The square root of 551811816 is about 23490.6750860847. The cubic root of 551811816 is about 820.2199568571.

The spelling of 551811816 in words is "five hundred fifty-one million, eight hundred eleven thousand, eight hundred sixteen".