870784721 has 2 divisors, whose sum is σ = 870784722. Its totient is φ = 870784720.

The previous prime is 870784657. The next prime is 870784723. The reversal of 870784721 is 127487078.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628204096 + 242580625 = 25064^2 + 15575^2 .

It is a cyclic number.

It is not a de Polignac number, because 870784721 - 2⁶ = 870784657 is a prime.

Together with 870784723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (870784723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 435392360 + 435392361.

It is an arithmetic number, because the mean of its divisors is an integer number (435392361).

Almost surely, 2^870784721 is an apocalyptic number.

It is an amenable number.

870784721 is a deficient number, since it is larger than the sum of its proper divisors (1).

870784721 is an equidigital number, since it uses as much as digits as its factorization.

870784721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 175616, while the sum is 44.

The square root of 870784721 is about 29509.0616760344. The cubic root of 870784721 is about 954.9272062421.

The spelling of 870784721 in words is "eight hundred seventy million, seven hundred eighty-four thousand, seven hundred twenty-one".