16655511521 has 8 divisors (see below), whose sum is σ = 18264780288. Its totient is φ = 15062098000.

The previous prime is 16655511517. The next prime is 16655511527. The reversal of 16655511521 is 12511555661.

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 16655511521 - 2² = 16655511517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16655511527) 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, 3961610 + ... + 3965811.

It is an arithmetic number, because the mean of its divisors is an integer number (2283097536).

Almost surely, 2^16655511521 is an apocalyptic number.

16655511521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16655511521 is a deficient number, since it is larger than the sum of its proper divisors (1609268767).

16655511521 is a wasteful number, since it uses less digits than its factorization.

16655511521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7927623.

The product of its digits is 45000, while the sum is 38.

The spelling of 16655511521 in words is "sixteen billion, six hundred fifty-five million, five hundred eleven thousand, five hundred twenty-one".