670550821 has 2 divisors, whose sum is σ = 670550822. Its totient is φ = 670550820.

The previous prime is 670550819. The next prime is 670550827. The reversal of 670550821 is 128055076.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 374229025 + 296321796 = 19345^2 + 17214^2 .

It is a cyclic number.

It is not a de Polignac number, because 670550821 - 2¹ = 670550819 is a prime.

Together with 670550819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (670550827) 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, 335275410 + 335275411.

It is an arithmetic number, because the mean of its divisors is an integer number (335275411).

Almost surely, 2^670550821 is an apocalyptic number.

It is an amenable number.

670550821 is a deficient number, since it is larger than the sum of its proper divisors (1).

670550821 is an equidigital number, since it uses as much as digits as its factorization.

670550821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 670550821 is about 25894.9960610153. The cubic root of 670550821 is about 875.2737411819.

The spelling of 670550821 in words is "six hundred seventy million, five hundred fifty thousand, eight hundred twenty-one".