28126021 has 16 divisors (see below), whose sum is σ = 36200448. Its totient is φ = 21207600.

The previous prime is 28126013. The next prime is 28126037. The reversal of 28126021 is 12062182.

It is a cyclic number.

It is not a de Polignac number, because 28126021 - 2³ = 28126013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28125983 and 28126001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28126051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3505 + ... + 8278.

It is an arithmetic number, because the mean of its divisors is an integer number (2262528).

Almost surely, 2^28126021 is an apocalyptic number.

It is an amenable number.

28126021 is a deficient number, since it is larger than the sum of its proper divisors (8074427).

28126021 is a wasteful number, since it uses less digits than its factorization.

28126021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11832.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 28126021 is about 5303.3971188286. The cubic root of 28126021 is about 304.1137796916.

The spelling of 28126021 in words is "twenty-eight million, one hundred twenty-six thousand, twenty-one".