20056721497 has 2 divisors, whose sum is σ = 20056721498. Its totient is φ = 20056721496.

The previous prime is 20056721491. The next prime is 20056721557. The reversal of 20056721497 is 79412765002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12629039641 + 7427681856 = 112379^2 + 86184^2 .

It is a cyclic number.

It is not a de Polignac number, because 20056721497 - 2⁷ = 20056721369 is a prime.

It is not a weakly prime, because it can be changed into another prime (20056721491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10028360748 + 10028360749.

It is an arithmetic number, because the mean of its divisors is an integer number (10028360749).

Almost surely, 2^20056721497 is an apocalyptic number.

It is an amenable number.

20056721497 is a deficient number, since it is larger than the sum of its proper divisors (1).

20056721497 is an equidigital number, since it uses as much as digits as its factorization.

20056721497 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 20056721497 in words is "twenty billion, fifty-six million, seven hundred twenty-one thousand, four hundred ninety-seven".