28721093 has 2 divisors, whose sum is σ = 28721094. Its totient is φ = 28721092.

The previous prime is 28721083. The next prime is 28721113. The reversal of 28721093 is 39012782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21224449 + 7496644 = 4607^2 + 2738^2 .

It is a cyclic number.

It is not a de Polignac number, because 28721093 - 2⁶ = 28721029 is a prime.

It is a super-2 number, since 2×28721093² = 1649802366229298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28721083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14360546 + 14360547.

It is an arithmetic number, because the mean of its divisors is an integer number (14360547).

Almost surely, 2^28721093 is an apocalyptic number.

It is an amenable number.

28721093 is a deficient number, since it is larger than the sum of its proper divisors (1).

28721093 is an equidigital number, since it uses as much as digits as its factorization.

28721093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 28721093 is about 5359.2063778138. The cubic root of 28721093 is about 306.2435762640.

The spelling of 28721093 in words is "twenty-eight million, seven hundred twenty-one thousand, ninety-three".