43818221691 has 6 divisors (see below), whose sum is σ = 63292986900. Its totient is φ = 29212147788.

The previous prime is 43818221677. The next prime is 43818221767. The reversal of 43818221691 is 19612281834.

It is not a de Polignac number, because 43818221691 - 2⁵ = 43818221659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (43818221791) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2434345641 + ... + 2434345658.

It is an arithmetic number, because the mean of its divisors is an integer number (10548831150).

Almost surely, 2^43818221691 is an apocalyptic number.

43818221691 is a deficient number, since it is larger than the sum of its proper divisors (19474765209).

43818221691 is a wasteful number, since it uses less digits than its factorization.

43818221691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4868691305 (or 4868691302 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The spelling of 43818221691 in words is "forty-three billion, eight hundred eighteen million, two hundred twenty-one thousand, six hundred ninety-one".