21028027 has 4 divisors (see below), whose sum is σ = 21112056. Its totient is φ = 20944000.

The previous prime is 21028009. The next prime is 21028043. The reversal of 21028027 is 72082012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21028027 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21027989 and 21028007.

It is not an unprimeable number, because it can be changed into a prime (21028087) 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 3 ways as a sum of consecutive naturals, for example, 41638 + ... + 42139.

It is an arithmetic number, because the mean of its divisors is an integer number (5278014).

Almost surely, 2^21028027 is an apocalyptic number.

21028027 is a deficient number, since it is larger than the sum of its proper divisors (84029).

21028027 is an equidigital number, since it uses as much as digits as its factorization.

21028027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84028.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 21028027 is about 4585.6326717259. The cubic root of 21028027 is about 276.0151001680.

The spelling of 21028027 in words is "twenty-one million, twenty-eight thousand, twenty-seven".