551661605587 has 4 divisors (see below), whose sum is σ = 551678046480. Its totient is φ = 551645164696.

The previous prime is 551661605563. The next prime is 551661605591. The reversal of 551661605587 is 785506166155.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 785506166155 = 5 ⋅157101233231.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551661605587 is a prime.

It is a super-2 number, since 2×551661605587² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551661608587) 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, 8170012 + ... + 8237257.

It is an arithmetic number, because the mean of its divisors is an integer number (137919511620).

Almost surely, 2^551661605587 is an apocalyptic number.

551661605587 is a deficient number, since it is larger than the sum of its proper divisors (16440893).

551661605587 is a wasteful number, since it uses less digits than its factorization.

551661605587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16440892.

The product of its (nonzero) digits is 7560000, while the sum is 55.

It can be divided in two parts, 55166 and 1605587, that added together give a triangular number (1660753 = T₁₈₂₂).

The spelling of 551661605587 in words is "five hundred fifty-one billion, six hundred sixty-one million, six hundred five thousand, five hundred eighty-seven".