28721743 has 2 divisors, whose sum is σ = 28721744. Its totient is φ = 28721742.

The previous prime is 28721723. The next prime is 28721767. The reversal of 28721743 is 34712782.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28721743 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28721699 and 28721708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28721713) 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, 14360871 + 14360872.

It is an arithmetic number, because the mean of its divisors is an integer number (14360872).

Almost surely, 2^28721743 is an apocalyptic number.

28721743 is a deficient number, since it is larger than the sum of its proper divisors (1).

28721743 is an equidigital number, since it uses as much as digits as its factorization.

28721743 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 34.

The square root of 28721743 is about 5359.2670207781. The cubic root of 28721743 is about 306.2458864920.

The spelling of 28721743 in words is "twenty-eight million, seven hundred twenty-one thousand, seven hundred forty-three".