8742821 has 2 divisors, whose sum is σ = 8742822. Its totient is φ = 8742820.

The previous prime is 8742817. The next prime is 8742847. The reversal of 8742821 is 1282478.

8742821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5452225 + 3290596 = 2335^2 + 1814^2 .

It is a cyclic number.

It is not a de Polignac number, because 8742821 - 2² = 8742817 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 (8742121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4371410 + 4371411.

It is an arithmetic number, because the mean of its divisors is an integer number (4371411).

Almost surely, 2^8742821 is an apocalyptic number.

It is an amenable number.

8742821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8742821 is an equidigital number, since it uses as much as digits as its factorization.

8742821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7168, while the sum is 32.

The square root of 8742821 is about 2956.8261700682. The cubic root of 8742821 is about 206.0078939382.

The spelling of 8742821 in words is "eight million, seven hundred forty-two thousand, eight hundred twenty-one".