28229681 has 2 divisors, whose sum is σ = 28229682. Its totient is φ = 28229680.

The previous prime is 28229659. The next prime is 28229693. The reversal of 28229681 is 18692282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27615025 + 614656 = 5255^2 + 784^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28229681 is a prime.

It is a super-2 number, since 2×28229681² = 1593829778723522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28229381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14114840 + 14114841.

It is an arithmetic number, because the mean of its divisors is an integer number (14114841).

Almost surely, 2^28229681 is an apocalyptic number.

It is an amenable number.

28229681 is a deficient number, since it is larger than the sum of its proper divisors (1).

28229681 is an equidigital number, since it uses as much as digits as its factorization.

28229681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 38.

The square root of 28229681 is about 5313.1611118053. The cubic root of 28229681 is about 304.4869310065.

The spelling of 28229681 in words is "twenty-eight million, two hundred twenty-nine thousand, six hundred eighty-one".