28620243721 has 4 divisors (see below), whose sum is σ = 28702250500. Its totient is φ = 28538236944.

The previous prime is 28620243713. The next prime is 28620243727. The reversal of 28620243721 is 12734202682.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9827946496 + 18792297225 = 99136^2 + 137085^2 .

It is a cyclic number.

It is not a de Polignac number, because 28620243721 - 2³ = 28620243713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28620243727) 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, 41002866 + ... + 41003563.

It is an arithmetic number, because the mean of its divisors is an integer number (7175562625).

Almost surely, 2^28620243721 is an apocalyptic number.

It is an amenable number.

28620243721 is a deficient number, since it is larger than the sum of its proper divisors (82006779).

28620243721 is an equidigital number, since it uses as much as digits as its factorization.

28620243721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82006778.

The product of its (nonzero) digits is 64512, while the sum is 37.

It can be divided in two parts, 286202 and 43721, that added together give a palindrome (329923).

The spelling of 28620243721 in words is "twenty-eight billion, six hundred twenty million, two hundred forty-three thousand, seven hundred twenty-one".