551661605591 has 2 divisors, whose sum is σ = 551661605592. Its totient is φ = 551661605590.

The previous prime is 551661605563. The next prime is 551661605609. The reversal of 551661605591 is 195506166155.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 551661605591 - 2¹⁸ = 551661343447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (551661605501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275830802795 + 275830802796.

It is an arithmetic number, because the mean of its divisors is an integer number (275830802796).

Almost surely, 2^551661605591 is an apocalyptic number.

551661605591 is a deficient number, since it is larger than the sum of its proper divisors (1).

551661605591 is an equidigital number, since it uses as much as digits as its factorization.

551661605591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1215000, while the sum is 50.

The spelling of 551661605591 in words is "five hundred fifty-one billion, six hundred sixty-one million, six hundred five thousand, five hundred ninety-one".