28160021 has 2 divisors, whose sum is σ = 28160022. Its totient is φ = 28160020.

The previous prime is 28160009. The next prime is 28160023. The reversal of 28160021 is 12006182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20151121 + 8008900 = 4489^2 + 2830^2 .

It is a cyclic number.

It is not a de Polignac number, because 28160021 - 2²² = 23965717 is a prime.

Together with 28160023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 28159975 and 28160002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28160023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14080010 + 14080011.

It is an arithmetic number, because the mean of its divisors is an integer number (14080011).

Almost surely, 2^28160021 is an apocalyptic number.

It is an amenable number.

28160021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28160021 is an equidigital number, since it uses as much as digits as its factorization.

28160021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 28160021 is about 5306.6016432365. The cubic root of 28160021 is about 304.2362724878.

The spelling of 28160021 in words is "twenty-eight million, one hundred sixty thousand, twenty-one".