20947381757 has 2 divisors, whose sum is σ = 20947381758. Its totient is φ = 20947381756.

The previous prime is 20947381751. The next prime is 20947381843. The reversal of 20947381757 is 75718374902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12301915396 + 8645466361 = 110914^2 + 92981^2 .

It is a cyclic number.

It is not a de Polignac number, because 20947381757 - 2²⁶ = 20880272893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20947381699 and 20947381708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20947381751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10473690878 + 10473690879.

It is an arithmetic number, because the mean of its divisors is an integer number (10473690879).

Almost surely, 2^20947381757 is an apocalyptic number.

It is an amenable number.

20947381757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20947381757 is an equidigital number, since it uses as much as digits as its factorization.

20947381757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2963520, while the sum is 53.

The spelling of 20947381757 in words is "twenty billion, nine hundred forty-seven million, three hundred eighty-one thousand, seven hundred fifty-seven".