69728221 has 2 divisors, whose sum is σ = 69728222. Its totient is φ = 69728220.

The previous prime is 69728189. The next prime is 69728227. The reversal of 69728221 is 12282796.

69728221 is nontrivially palindromic in base 6.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65772100 + 3956121 = 8110^2 + 1989^2 .

It is a cyclic number.

It is not a de Polignac number, because 69728221 - 2⁵ = 69728189 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (69728227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34864110 + 34864111.

It is an arithmetic number, because the mean of its divisors is an integer number (34864111).

Almost surely, 2^69728221 is an apocalyptic number.

It is an amenable number.

69728221 is a deficient number, since it is larger than the sum of its proper divisors (1).

69728221 is an equidigital number, since it uses as much as digits as its factorization.

69728221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 37.

The square root of 69728221 is about 8350.3425678232. The cubic root of 69728221 is about 411.5944673512.

The spelling of 69728221 in words is "sixty-nine million, seven hundred twenty-eight thousand, two hundred twenty-one".