5551661101561 has 8 divisors (see below), whose sum is σ = 5815795132800. Its totient is φ = 5292373566480.

The previous prime is 5551661101537. The next prime is 5551661101577. The reversal of 5551661101561 is 1651011661555.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 5551661101561 - 2¹⁷ = 5551660970489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5551661107561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1211621695 + ... + 1211626276.

It is an arithmetic number, because the mean of its divisors is an integer number (726974391600).

Almost surely, 2^{5551661101561} is an apocalyptic number.

It is an amenable number.

5551661101561 is a deficient number, since it is larger than the sum of its proper divisors (264134031239).

5551661101561 is a wasteful number, since it uses less digits than its factorization.

5551661101561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2423248079.

The product of its (nonzero) digits is 135000, while the sum is 43.

The spelling of 5551661101561 in words is "five trillion, five hundred fifty-one billion, six hundred sixty-one million, one hundred one thousand, five hundred sixty-one".