428939221 has 2 divisors, whose sum is σ = 428939222. Its totient is φ = 428939220.

The previous prime is 428939179. The next prime is 428939237. The reversal of 428939221 is 122939824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 412536721 + 16402500 = 20311^2 + 4050^2 .

It is a cyclic number.

It is not a de Polignac number, because 428939221 - 2⁹ = 428938709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428939321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214469610 + 214469611.

It is an arithmetic number, because the mean of its divisors is an integer number (214469611).

Almost surely, 2^428939221 is an apocalyptic number.

It is an amenable number.

428939221 is a deficient number, since it is larger than the sum of its proper divisors (1).

428939221 is an equidigital number, since it uses as much as digits as its factorization.

428939221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 40.

The square root of 428939221 is about 20710.8479063509. The cubic root of 428939221 is about 754.1630542539.

The spelling of 428939221 in words is "four hundred twenty-eight million, nine hundred thirty-nine thousand, two hundred twenty-one".