28721567807423 has 4 divisors (see below), whose sum is σ = 28721579865000. Its totient is φ = 28721555749848.

The previous prime is 28721567807341. The next prime is 28721567807521. The reversal of 28721567807423 is 32470876512782.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 28721567807423 - 2¹⁶ = 28721567741887 is a prime.

It is a super-2 number, since 2×28721567807423² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28721567867423) 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, 1127540 + ... + 7662537.

It is an arithmetic number, because the mean of its divisors is an integer number (7180394966250).

Almost surely, 2^{28721567807423} is an apocalyptic number.

28721567807423 is a deficient number, since it is larger than the sum of its proper divisors (12057577).

28721567807423 is an equidigital number, since it uses as much as digits as its factorization.

28721567807423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12057576.

The product of its (nonzero) digits is 63221760, while the sum is 62.

The spelling of 28721567807423 in words is "twenty-eight trillion, seven hundred twenty-one billion, five hundred sixty-seven million, eight hundred seven thousand, four hundred twenty-three".