8438921 has 2 divisors, whose sum is σ = 8438922. Its totient is φ = 8438920.

The previous prime is 8438917. The next prime is 8438929. The reversal of 8438921 is 1298348.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8065600 + 373321 = 2840^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 8438921 - 2² = 8438917 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (8438929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4219460 + 4219461.

It is an arithmetic number, because the mean of its divisors is an integer number (4219461).

Almost surely, 2^8438921 is an apocalyptic number.

It is an amenable number.

8438921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8438921 is an equidigital number, since it uses as much as digits as its factorization.

8438921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 35.

The square root of 8438921 is about 2904.9820997727. The cubic root of 8438921 is about 203.5927493066.

The spelling of 8438921 in words is "eight million, four hundred thirty-eight thousand, nine hundred twenty-one".