28038421 has 2 divisors, whose sum is σ = 28038422. Its totient is φ = 28038420.

The previous prime is 28038401. The next prime is 28038499. The reversal of 28038421 is 12483082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23415921 + 4622500 = 4839^2 + 2150^2 .

It is a cyclic number.

It is not a de Polignac number, because 28038421 - 2⁹ = 28037909 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28038421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28038401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14019210 + 14019211.

It is an arithmetic number, because the mean of its divisors is an integer number (14019211).

Almost surely, 2^28038421 is an apocalyptic number.

It is an amenable number.

28038421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28038421 is an equidigital number, since it uses as much as digits as its factorization.

28038421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 28038421 is about 5295.1318208332. The cubic root of 28038421 is about 303.7977251186.

The spelling of 28038421 in words is "twenty-eight million, thirty-eight thousand, four hundred twenty-one".