20188324861 has 4 divisors (see below), whose sum is σ = 20657820832. Its totient is φ = 19718828892.

The previous prime is 20188324853. The next prime is 20188324901. The reversal of 20188324861 is 16842388102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20188324861 - 2³ = 20188324853 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 469495927 = 20188324861 / (2 + 0 + 1 + 8 + 8 + 3 + 2 + 4 + 8 + 6 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20188324811) 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, 234747921 + ... + 234748006.

It is an arithmetic number, because the mean of its divisors is an integer number (5164455208).

Almost surely, 2^20188324861 is an apocalyptic number.

It is an amenable number.

20188324861 is a deficient number, since it is larger than the sum of its proper divisors (469495971).

20188324861 is an equidigital number, since it uses as much as digits as its factorization.

20188324861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469495970.

The product of its (nonzero) digits is 147456, while the sum is 43.

The spelling of 20188324861 in words is "twenty billion, one hundred eighty-eight million, three hundred twenty-four thousand, eight hundred sixty-one".