28165571216641 has 4 divisors (see below), whose sum is σ = 28165912770352. Its totient is φ = 28165229662932.

The previous prime is 28165571216639. The next prime is 28165571216647. The reversal of 28165571216641 is 14661217556182.

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 a cyclic number.

It is not a de Polignac number, because 28165571216641 - 2¹ = 28165571216639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28165571216647) 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, 170653131 + ... + 170818096.

It is an arithmetic number, because the mean of its divisors is an integer number (7041478192588).

Almost surely, 2^{28165571216641} is an apocalyptic number.

It is an amenable number.

28165571216641 is a deficient number, since it is larger than the sum of its proper divisors (341553711).

28165571216641 is an equidigital number, since it uses as much as digits as its factorization.

28165571216641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341553710.

The product of its digits is 4838400, while the sum is 55.

The spelling of 28165571216641 in words is "twenty-eight trillion, one hundred sixty-five billion, five hundred seventy-one million, two hundred sixteen thousand, six hundred forty-one".