20513440709 has 2 divisors, whose sum is σ = 20513440710. Its totient is φ = 20513440708.

The previous prime is 20513440697. The next prime is 20513440733. The reversal of 20513440709 is 90704431502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20394696100 + 118744609 = 142810^2 + 10897^2 .

It is a cyclic number.

It is not a de Polignac number, because 20513440709 - 2¹⁶ = 20513375173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20513440769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256720354 + 10256720355.

It is an arithmetic number, because the mean of its divisors is an integer number (10256720355).

Almost surely, 2^20513440709 is an apocalyptic number.

It is an amenable number.

20513440709 is a deficient number, since it is larger than the sum of its proper divisors (1).

20513440709 is an equidigital number, since it uses as much as digits as its factorization.

20513440709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 20513440709 in words is "twenty billion, five hundred thirteen million, four hundred forty thousand, seven hundred nine".