1091643859 has 2 divisors, whose sum is σ = 1091643860. Its totient is φ = 1091643858.

The previous prime is 1091643857. The next prime is 1091643863. The reversal of 1091643859 is 9583461901.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1091643859 - 2¹ = 1091643857 is a prime.

Together with 1091643857, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1091643857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545821929 + 545821930.

It is an arithmetic number, because the mean of its divisors is an integer number (545821930).

Almost surely, 2^1091643859 is an apocalyptic number.

1091643859 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091643859 is an equidigital number, since it uses as much as digits as its factorization.

1091643859 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 46.

The square root of 1091643859 is about 33040.0341858177. The cubic root of 1091643859 is about 1029.6595660675.

The spelling of 1091643859 in words is "one billion, ninety-one million, six hundred forty-three thousand, eight hundred fifty-nine".