551666261 has 4 divisors (see below), whose sum is σ = 551757024. Its totient is φ = 551575500.

The previous prime is 551666251. The next prime is 551666281. The reversal of 551666261 is 162666155.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 551666261 - 2¹⁰ = 551665237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551666231) 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, 35555 + ... + 48656.

It is an arithmetic number, because the mean of its divisors is an integer number (137939256).

Almost surely, 2^551666261 is an apocalyptic number.

It is an amenable number.

551666261 is a deficient number, since it is larger than the sum of its proper divisors (90763).

551666261 is an equidigital number, since it uses as much as digits as its factorization.

551666261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90762.

The product of its digits is 64800, while the sum is 38.

The square root of 551666261 is about 23487.5767375010. The cubic root of 551666261 is about 820.1478322601.

The spelling of 551666261 in words is "five hundred fifty-one million, six hundred sixty-six thousand, two hundred sixty-one".