28047421 has 2 divisors, whose sum is σ = 28047422. Its totient is φ = 28047420.

The previous prime is 28047413. The next prime is 28047431. The reversal of 28047421 is 12474082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27941796 + 105625 = 5286^2 + 325^2 .

It is a cyclic number.

It is not a de Polignac number, because 28047421 - 2³ = 28047413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28047421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28047431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14023710 + 14023711.

It is an arithmetic number, because the mean of its divisors is an integer number (14023711).

Almost surely, 2^28047421 is an apocalyptic number.

It is an amenable number.

28047421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28047421 is an equidigital number, since it uses as much as digits as its factorization.

28047421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 28047421 is about 5295.9815898472. The cubic root of 28047421 is about 303.8302267947.

The spelling of 28047421 in words is "twenty-eight million, forty-seven thousand, four hundred twenty-one".