28231242021 has 12 divisors (see below), whose sum is σ = 40790287980. Its totient is φ = 18815369280.

The previous prime is 28231241999. The next prime is 28231242023. The reversal of 28231242021 is 12024213282.

28231242021 is a `hidden beast` number, since 2 + 8 + 231 + 2 + 420 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20259252225 + 7971989796 = 142335^2 + 89286^2 .

It is not a de Polignac number, because 28231242021 - 2⁵ = 28231241989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28231242023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 422016 + ... + 484313.

It is an arithmetic number, because the mean of its divisors is an integer number (3399190665).

Almost surely, 2^28231242021 is an apocalyptic number.

It is an amenable number.

28231242021 is a deficient number, since it is larger than the sum of its proper divisors (12559045959).

28231242021 is a wasteful number, since it uses less digits than its factorization.

28231242021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909796 (or 909793 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The spelling of 28231242021 in words is "twenty-eight billion, two hundred thirty-one million, two hundred forty-two thousand, twenty-one".