16660636451 has 4 divisors (see below), whose sum is σ = 16694025000. Its totient is φ = 16627247904.

The previous prime is 16660636411. The next prime is 16660636453. The reversal of 16660636451 is 15463606661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15463606661 = 27509 ⋅562129.

It is a cyclic number.

It is not a de Polignac number, because 16660636451 - 2³⁰ = 15586894627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16660636453) 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, 16693526 + ... + 16694523.

It is an arithmetic number, because the mean of its divisors is an integer number (4173506250).

Almost surely, 2^16660636451 is an apocalyptic number.

16660636451 is a deficient number, since it is larger than the sum of its proper divisors (33388549).

16660636451 is an equidigital number, since it uses as much as digits as its factorization.

16660636451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33388548.

The product of its (nonzero) digits is 466560, while the sum is 44.

The spelling of 16660636451 in words is "sixteen billion, six hundred sixty million, six hundred thirty-six thousand, four hundred fifty-one".