20491019771 has 2 divisors, whose sum is σ = 20491019772. Its totient is φ = 20491019770.

The previous prime is 20491019767. The next prime is 20491019833. The reversal of 20491019771 is 17791019402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20491019771 - 2² = 20491019767 is a prime.

It is not a weakly prime, because it can be changed into another prime (20491019741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10245509885 + 10245509886.

It is an arithmetic number, because the mean of its divisors is an integer number (10245509886).

Almost surely, 2^20491019771 is an apocalyptic number.

20491019771 is a deficient number, since it is larger than the sum of its proper divisors (1).

20491019771 is an equidigital number, since it uses as much as digits as its factorization.

20491019771 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31752, while the sum is 41.

The spelling of 20491019771 in words is "twenty billion, four hundred ninety-one million, nineteen thousand, seven hundred seventy-one".