321668891 has 2 divisors, whose sum is σ = 321668892. Its totient is φ = 321668890.

The previous prime is 321668881. The next prime is 321668933. The reversal of 321668891 is 198866123.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 321668891 - 2⁶ = 321668827 is a prime.

It is not a weakly prime, because it can be changed into another prime (321668881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160834445 + 160834446.

It is an arithmetic number, because the mean of its divisors is an integer number (160834446).

Almost surely, 2^321668891 is an apocalyptic number.

321668891 is a deficient number, since it is larger than the sum of its proper divisors (1).

321668891 is an equidigital number, since it uses as much as digits as its factorization.

321668891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 44.

The square root of 321668891 is about 17935.1300803758. The cubic root of 321668891 is about 685.1773856412.

The spelling of 321668891 in words is "three hundred twenty-one million, six hundred sixty-eight thousand, eight hundred ninety-one".