842000821 has 2 divisors, whose sum is σ = 842000822. Its totient is φ = 842000820.

The previous prime is 842000791. The next prime is 842000833. The reversal of 842000821 is 128000248.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 832322500 + 9678321 = 28850^2 + 3111^2 .

It is a cyclic number.

It is not a de Polignac number, because 842000821 - 2¹⁵ = 841968053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (842003821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 421000410 + 421000411.

It is an arithmetic number, because the mean of its divisors is an integer number (421000411).

Almost surely, 2^842000821 is an apocalyptic number.

It is an amenable number.

842000821 is a deficient number, since it is larger than the sum of its proper divisors (1).

842000821 is an equidigital number, since it uses as much as digits as its factorization.

842000821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 842000821 is about 29017.2504038546. The cubic root of 842000821 is about 944.2873497567.

The spelling of 842000821 in words is "eight hundred forty-two million, eight hundred twenty-one", and thus it is an aban number.