20507724521 has 2 divisors, whose sum is σ = 20507724522. Its totient is φ = 20507724520.

The previous prime is 20507724511. The next prime is 20507724541. The reversal of 20507724521 is 12542770502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14541706921 + 5966017600 = 120589^2 + 77240^2 .

It is a cyclic number.

It is not a de Polignac number, because 20507724521 - 2²² = 20503530217 is a prime.

It is not a weakly prime, because it can be changed into another prime (20507724511) 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, 10253862260 + 10253862261.

It is an arithmetic number, because the mean of its divisors is an integer number (10253862261).

Almost surely, 2^20507724521 is an apocalyptic number.

It is an amenable number.

20507724521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20507724521 is an equidigital number, since it uses as much as digits as its factorization.

20507724521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 39200, while the sum is 35.

The spelling of 20507724521 in words is "twenty billion, five hundred seven million, seven hundred twenty-four thousand, five hundred twenty-one".