28373871821 has 4 divisors (see below), whose sum is σ = 28376776032. Its totient is φ = 28370967612.

The previous prime is 28373871809. The next prime is 28373871839. The reversal of 28373871821 is 12817837382.

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 a de Polignac number, because none of the positive numbers 2^k-28373871821 is a prime.

It is a super-2 number, since 2×28373871821² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28373871821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28373871881) 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, 1437401 + ... + 1457006.

It is an arithmetic number, because the mean of its divisors is an integer number (7094194008).

Almost surely, 2^28373871821 is an apocalyptic number.

It is an amenable number.

28373871821 is a deficient number, since it is larger than the sum of its proper divisors (2904211).

28373871821 is an equidigital number, since it uses as much as digits as its factorization.

28373871821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2904210.

The product of its digits is 903168, while the sum is 50.

The spelling of 28373871821 in words is "twenty-eight billion, three hundred seventy-three million, eight hundred seventy-one thousand, eight hundred twenty-one".