551661666511 has 4 divisors (see below), whose sum is σ = 552858330024. Its totient is φ = 550465003000.

The previous prime is 551661666503. The next prime is 551661666529. The reversal of 551661666511 is 115666166155.

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

It is a cyclic number.

It is not a de Polignac number, because 551661666511 - 2³ = 551661666503 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551661666571) 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, 598331065 + ... + 598331986.

It is an arithmetic number, because the mean of its divisors is an integer number (138214582506).

Almost surely, 2^551661666511 is an apocalyptic number.

551661666511 is a deficient number, since it is larger than the sum of its proper divisors (1196663513).

551661666511 is a wasteful number, since it uses less digits than its factorization.

551661666511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1196663512.

The product of its digits is 972000, while the sum is 49.

The spelling of 551661666511 in words is "five hundred fifty-one billion, six hundred sixty-one million, six hundred sixty-six thousand, five hundred eleven".