385817891 has 2 divisors, whose sum is σ = 385817892. Its totient is φ = 385817890.

The previous prime is 385817837. The next prime is 385817963. The reversal of 385817891 is 198718583.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-385817891 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (385817291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 192908945 + 192908946.

It is an arithmetic number, because the mean of its divisors is an integer number (192908946).

Almost surely, 2^385817891 is an apocalyptic number.

385817891 is a deficient number, since it is larger than the sum of its proper divisors (1).

385817891 is an equidigital number, since it uses as much as digits as its factorization.

385817891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 50.

The square root of 385817891 is about 19642.2476056077. The cubic root of 385817891 is about 727.9934204966.

The spelling of 385817891 in words is "three hundred eighty-five million, eight hundred seventeen thousand, eight hundred ninety-one".