28726421 has 2 divisors, whose sum is σ = 28726422. Its totient is φ = 28726420.

The previous prime is 28726409. The next prime is 28726459. The reversal of 28726421 is 12462782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28462225 + 264196 = 5335^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 28726421 - 2¹⁴ = 28710037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28726121) 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 as a sum of consecutive naturals, namely, 14363210 + 14363211.

It is an arithmetic number, because the mean of its divisors is an integer number (14363211).

Almost surely, 2^28726421 is an apocalyptic number.

It is an amenable number.

28726421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28726421 is an equidigital number, since it uses as much as digits as its factorization.

28726421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 32.

The square root of 28726421 is about 5359.7034432886. The cubic root of 28726421 is about 306.2625119975.

The spelling of 28726421 in words is "twenty-eight million, seven hundred twenty-six thousand, four hundred twenty-one".