20591780940 has 144 divisors (see below), whose sum is σ = 64258713792. Its totient is φ = 5333672448.

The previous prime is 20591780939. The next prime is 20591780941. The reversal of 20591780940 is 4908719502.

It is an interprime number because it is at equal distance from previous prime (20591780939) and next prime (20591780941).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (20591780941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4506537 + ... + 4511103.

It is an arithmetic number, because the mean of its divisors is an integer number (446241068).

Almost surely, 2^20591780940 is an apocalyptic number.

20591780940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20591780940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32129356896).

20591780940 is an abundant number, since it is smaller than the sum of its proper divisors (43666932852).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20591780940 is a wasteful number, since it uses less digits than its factorization.

20591780940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5296 (or 5291 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The spelling of 20591780940 in words is "twenty billion, five hundred ninety-one million, seven hundred eighty thousand, nine hundred forty".