16251640566321 has 4 divisors (see below), whose sum is σ = 21668854088432. Its totient is φ = 10834427044212.

The previous prime is 16251640566289. The next prime is 16251640566349. The reversal of 16251640566321 is 12366504615261.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 16251640566321 - 2⁵ = 16251640566289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16251640567321) 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, 2708606761051 + ... + 2708606761056.

It is an arithmetic number, because the mean of its divisors is an integer number (5417213522108).

Almost surely, 2^{16251640566321} is an apocalyptic number.

It is an amenable number.

16251640566321 is a deficient number, since it is larger than the sum of its proper divisors (5417213522111).

16251640566321 is an equidigital number, since it uses as much as digits as its factorization.

16251640566321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5417213522110.

The product of its (nonzero) digits is 1555200, while the sum is 48.

The spelling of 16251640566321 in words is "sixteen trillion, two hundred fifty-one billion, six hundred forty million, five hundred sixty-six thousand, three hundred twenty-one".