20195809867 has 4 divisors (see below), whose sum is σ = 20196385776. Its totient is φ = 20195233960.

The previous prime is 20195809819. The next prime is 20195809883. The reversal of 20195809867 is 76890859102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20195809867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20195801867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231688 + ... + 306709.

It is an arithmetic number, because the mean of its divisors is an integer number (5049096444).

Almost surely, 2^20195809867 is an apocalyptic number.

20195809867 is a deficient number, since it is larger than the sum of its proper divisors (575909).

20195809867 is an equidigital number, since it uses as much as digits as its factorization.

20195809867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575908.

The product of its (nonzero) digits is 2177280, while the sum is 55.

The spelling of 20195809867 in words is "twenty billion, one hundred ninety-five million, eight hundred nine thousand, eight hundred sixty-seven".