684028221 has 16 divisors (see below), whose sum is σ = 917488704. Its totient is φ = 453302784.

The previous prime is 684028207. The next prime is 684028231. The reversal of 684028221 is 122820486.

It is a happy number.

684028221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 684028221 - 2¹⁸ = 683766077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684028231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 419610 + ... + 421236.

It is an arithmetic number, because the mean of its divisors is an integer number (57343044).

Almost surely, 2^684028221 is an apocalyptic number.

It is an amenable number.

684028221 is a deficient number, since it is larger than the sum of its proper divisors (233460483).

684028221 is a wasteful number, since it uses less digits than its factorization.

684028221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2380.

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 684028221 is about 26153.9331841312. The cubic root of 684028221 is about 881.0989288443.

The spelling of 684028221 in words is "six hundred eighty-four million, twenty-eight thousand, two hundred twenty-one".