20959731787 has 16 divisors (see below), whose sum is σ = 21383324928. Its totient is φ = 20540783520.

The previous prime is 20959731721. The next prime is 20959731799. The reversal of 20959731787 is 78713795902.

It is a cyclic number.

It is not a de Polignac number, because 20959731787 - 2³¹ = 18812248139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20959731707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7508362 + ... + 7511152.

It is an arithmetic number, because the mean of its divisors is an integer number (1336457808).

Almost surely, 2^20959731787 is an apocalyptic number.

20959731787 is a deficient number, since it is larger than the sum of its proper divisors (423593141).

20959731787 is a wasteful number, since it uses less digits than its factorization.

20959731787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3570.

The product of its (nonzero) digits is 6667920, while the sum is 58.

The spelling of 20959731787 in words is "twenty billion, nine hundred fifty-nine million, seven hundred thirty-one thousand, seven hundred eighty-seven".