670591891 has 2 divisors, whose sum is σ = 670591892. Its totient is φ = 670591890.

The previous prime is 670591879. The next prime is 670591913. The reversal of 670591891 is 198195076.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 670591891 - 2⁷ = 670591763 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (670591861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335295945 + 335295946.

It is an arithmetic number, because the mean of its divisors is an integer number (335295946).

Almost surely, 2^670591891 is an apocalyptic number.

670591891 is a deficient number, since it is larger than the sum of its proper divisors (1).

670591891 is an equidigital number, since it uses as much as digits as its factorization.

670591891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 46.

The square root of 670591891 is about 25895.7890592274. The cubic root of 670591891 is about 875.2916104507.

It can be divided in two parts, 6705 and 91891, that added together give a square (98596 = 314²).

The spelling of 670591891 in words is "six hundred seventy million, five hundred ninety-one thousand, eight hundred ninety-one".