28329421 has 2 divisors, whose sum is σ = 28329422. Its totient is φ = 28329420.

The previous prime is 28329419. The next prime is 28329461. The reversal of 28329421 is 12492382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24147396 + 4182025 = 4914^2 + 2045^2 .

It is a cyclic number.

It is not a de Polignac number, because 28329421 - 2¹ = 28329419 is a prime.

Together with 28329419, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28329461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14164710 + 14164711.

It is an arithmetic number, because the mean of its divisors is an integer number (14164711).

Almost surely, 2^28329421 is an apocalyptic number.

It is an amenable number.

28329421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28329421 is an equidigital number, since it uses as much as digits as its factorization.

28329421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 31.

The square root of 28329421 is about 5322.5389618114. The cubic root of 28329421 is about 304.8451099239.

The spelling of 28329421 in words is "twenty-eight million, three hundred twenty-nine thousand, four hundred twenty-one".