670821191 has 2 divisors, whose sum is σ = 670821192. Its totient is φ = 670821190.

The previous prime is 670821187. The next prime is 670821233. The reversal of 670821191 is 191128076.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 670821191 - 2² = 670821187 is a prime.

It is equal to p_34818821 and since 670821191 and 34818821 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (670821161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335410595 + 335410596.

It is an arithmetic number, because the mean of its divisors is an integer number (335410596).

Almost surely, 2^670821191 is an apocalyptic number.

670821191 is a deficient number, since it is larger than the sum of its proper divisors (1).

670821191 is an equidigital number, since it uses as much as digits as its factorization.

670821191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 35.

The square root of 670821191 is about 25900.2160415700. The cubic root of 670821191 is about 875.3913638662.

The spelling of 670821191 in words is "six hundred seventy million, eight hundred twenty-one thousand, one hundred ninety-one".