28695721 has 2 divisors, whose sum is σ = 28695722. Its totient is φ = 28695720.

The previous prime is 28695701. The next prime is 28695727. The reversal of 28695721 is 12759682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27405225 + 1290496 = 5235^2 + 1136^2 .

It is a cyclic number.

It is not a de Polignac number, because 28695721 - 2⁹ = 28695209 is a prime.

It is not a weakly prime, because it can be changed into another prime (28695727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14347860 + 14347861.

It is an arithmetic number, because the mean of its divisors is an integer number (14347861).

Almost surely, 2^28695721 is an apocalyptic number.

It is an amenable number.

28695721 is a deficient number, since it is larger than the sum of its proper divisors (1).

28695721 is an equidigital number, since it uses as much as digits as its factorization.

28695721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 40.

The square root of 28695721 is about 5356.8387132711. The cubic root of 28695721 is about 306.1533719308.

The spelling of 28695721 in words is "twenty-eight million, six hundred ninety-five thousand, seven hundred twenty-one".