16611105521 has 4 divisors (see below), whose sum is σ = 16612719732. Its totient is φ = 16609491312.

The previous prime is 16611105481. The next prime is 16611105529. The reversal of 16611105521 is 12550111661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12550111661 = 47287 ⋅265403.

It can be written as a sum of positive squares in 2 ways, for example, as 2458672225 + 14152433296 = 49585^2 + 118964^2 .

It is a cyclic number.

It is not a de Polignac number, because 16611105521 - 2¹⁸ = 16610843377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16611105529) 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, 791570 + ... + 812283.

It is an arithmetic number, because the mean of its divisors is an integer number (4153179933).

Almost surely, 2^16611105521 is an apocalyptic number.

It is an amenable number.

16611105521 is a deficient number, since it is larger than the sum of its proper divisors (1614211).

16611105521 is a wasteful number, since it uses less digits than its factorization.

16611105521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1614210.

The product of its (nonzero) digits is 1800, while the sum is 29.

The spelling of 16611105521 in words is "sixteen billion, six hundred eleven million, one hundred five thousand, five hundred twenty-one".