16561526521 has 8 divisors (see below), whose sum is σ = 17350932224. Its totient is φ = 15788068560.

The previous prime is 16561526489. The next prime is 16561526537. The reversal of 16561526521 is 12562516561.

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 16561526521 - 2⁵ = 16561526489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16561526551) 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, 3984810 + ... + 3988963.

It is an arithmetic number, because the mean of its divisors is an integer number (2168866528).

Almost surely, 2^16561526521 is an apocalyptic number.

It is an amenable number.

16561526521 is a deficient number, since it is larger than the sum of its proper divisors (789405703).

16561526521 is an equidigital number, since it uses as much as digits as its factorization.

16561526521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7973871.

The product of its digits is 108000, while the sum is 40.

The spelling of 16561526521 in words is "sixteen billion, five hundred sixty-one million, five hundred twenty-six thousand, five hundred twenty-one".