20904923771 has 2 divisors, whose sum is σ = 20904923772. Its totient is φ = 20904923770.

The previous prime is 20904923759. The next prime is 20904923839. The reversal of 20904923771 is 17732940902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20904923771 is a prime.

It is not a weakly prime, because it can be changed into another prime (20904923471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10452461885 + 10452461886.

It is an arithmetic number, because the mean of its divisors is an integer number (10452461886).

Almost surely, 2^20904923771 is an apocalyptic number.

20904923771 is a deficient number, since it is larger than the sum of its proper divisors (1).

20904923771 is an equidigital number, since it uses as much as digits as its factorization.

20904923771 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 44.

The spelling of 20904923771 in words is "twenty billion, nine hundred four million, nine hundred twenty-three thousand, seven hundred seventy-one".