15661010561 has 8 divisors (see below), whose sum is σ = 17945032704. Its totient is φ = 13388672160.

The previous prime is 15661010539. The next prime is 15661010587. The reversal of 15661010561 is 16501016651.

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 15661010561 - 2¹⁸ = 15660748417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15661010501) 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, 2918060 + ... + 2923421.

It is an arithmetic number, because the mean of its divisors is an integer number (2243129088).

Almost surely, 2^15661010561 is an apocalyptic number.

It is an amenable number.

15661010561 is a deficient number, since it is larger than the sum of its proper divisors (2284022143).

15661010561 is an equidigital number, since it uses as much as digits as its factorization.

15661010561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5841871.

The product of its (nonzero) digits is 5400, while the sum is 32.

The spelling of 15661010561 in words is "fifteen billion, six hundred sixty-one million, ten thousand, five hundred sixty-one".