551506666 has 4 divisors (see below), whose sum is σ = 827260002. Its totient is φ = 275753332.

The previous prime is 551506661. The next prime is 551506667. The reversal of 551506666 is 666605155.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 523723225 + 27783441 = 22885^2 + 5271^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (551506661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 137876665 + ... + 137876668.

Almost surely, 2^551506666 is an apocalyptic number.

551506666 is a deficient number, since it is larger than the sum of its proper divisors (275753336).

551506666 is a wasteful number, since it uses less digits than its factorization.

551506666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275753335.

The product of its (nonzero) digits is 162000, while the sum is 40.

The square root of 551506666 is about 23484.1790573995. The cubic root of 551506666 is about 820.0687360584.

It can be divided in two parts, 55150 and 6666, that added together give a palindrome (61816).

The spelling of 551506666 in words is "five hundred fifty-one million, five hundred six thousand, six hundred sixty-six".