678284221 has 2 divisors, whose sum is σ = 678284222. Its totient is φ = 678284220.

The previous prime is 678284209. The next prime is 678284227. The reversal of 678284221 is 122482876.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 675428121 + 2856100 = 25989^2 + 1690^2 .

It is a cyclic number.

It is not a de Polignac number, because 678284221 - 2²⁷ = 544066493 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 (678284227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339142110 + 339142111.

It is an arithmetic number, because the mean of its divisors is an integer number (339142111).

Almost surely, 2^678284221 is an apocalyptic number.

It is an amenable number.

678284221 is a deficient number, since it is larger than the sum of its proper divisors (1).

678284221 is an equidigital number, since it uses as much as digits as its factorization.

678284221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 86016, while the sum is 40.

The square root of 678284221 is about 26043.8902815996. The cubic root of 678284221 is about 878.6257048301.

The spelling of 678284221 in words is "six hundred seventy-eight million, two hundred eighty-four thousand, two hundred twenty-one".