870001021 has 2 divisors, whose sum is σ = 870001022. Its totient is φ = 870001020.

The previous prime is 870001007. The next prime is 870001031. The reversal of 870001021 is 120100078.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 735765625 + 134235396 = 27125^2 + 11586^2 .

It is a cyclic number.

It is not a de Polignac number, because 870001021 - 2⁷ = 870000893 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 870001021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (870001031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 435000510 + 435000511.

It is an arithmetic number, because the mean of its divisors is an integer number (435000511).

Almost surely, 2^870001021 is an apocalyptic number.

It is an amenable number.

870001021 is a deficient number, since it is larger than the sum of its proper divisors (1).

870001021 is an equidigital number, since it uses as much as digits as its factorization.

870001021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 870001021 is about 29495.7797150711. The cubic root of 870001021 is about 954.6406443794.

Adding to 870001021 its reverse (120100078), we get a palindrome (990101099).

The spelling of 870001021 in words is "eight hundred seventy million, one thousand, twenty-one".