20591091940 has 12 divisors (see below), whose sum is σ = 43241293116. Its totient is φ = 8236436768.

The previous prime is 20591091881. The next prime is 20591091943. The reversal of 20591091940 is 4919019502.

It can be written as a sum of positive squares in 2 ways, for example, as 11565711936 + 9025380004 = 107544^2 + 95002^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20591091893 and 20591091902.

It is not an unprimeable number, because it can be changed into a prime (20591091943) 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, 514777279 + ... + 514777318.

It is an arithmetic number, because the mean of its divisors is an integer number (3603441093).

Almost surely, 2^20591091940 is an apocalyptic number.

20591091940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20591091940 is an abundant number, since it is smaller than the sum of its proper divisors (22650201176).

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

20591091940 is a wasteful number, since it uses less digits than its factorization.

20591091940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029554606 (or 1029554604 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 40.

The spelling of 20591091940 in words is "twenty billion, five hundred ninety-one million, ninety-one thousand, nine hundred forty".