16531322661 has 24 divisors (see below), whose sum is σ = 28230833280. Its totient is φ = 9120728736.

The previous prime is 16531322659. The next prime is 16531322779. The reversal of 16531322661 is 16622313561.

16531322661 is a `hidden beast` number, since 1 + 65 + 313 + 226 + 61 = 666.

It is not a de Polignac number, because 16531322661 - 2¹ = 16531322659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16531322651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4522345 + ... + 4525998.

It is an arithmetic number, because the mean of its divisors is an integer number (1176284720).

Almost surely, 2^16531322661 is an apocalyptic number.

It is an amenable number.

16531322661 is a deficient number, since it is larger than the sum of its proper divisors (11699510619).

16531322661 is a wasteful number, since it uses less digits than its factorization.

16531322661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9048385 (or 9048382 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The spelling of 16531322661 in words is "sixteen billion, five hundred thirty-one million, three hundred twenty-two thousand, six hundred sixty-one".