20615506729 has 2 divisors, whose sum is σ = 20615506730. Its totient is φ = 20615506728.

The previous prime is 20615506697. The next prime is 20615506789. The reversal of 20615506729 is 92760551602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20245021225 + 370485504 = 142285^2 + 19248^2 .

It is a cyclic number.

It is not a de Polignac number, because 20615506729 - 2⁵ = 20615506697 is a prime.

It is not a weakly prime, because it can be changed into another prime (20615506789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10307753364 + 10307753365.

It is an arithmetic number, because the mean of its divisors is an integer number (10307753365).

Almost surely, 2^20615506729 is an apocalyptic number.

It is an amenable number.

20615506729 is a deficient number, since it is larger than the sum of its proper divisors (1).

20615506729 is an equidigital number, since it uses as much as digits as its factorization.

20615506729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 226800, while the sum is 43.

The spelling of 20615506729 in words is "twenty billion, six hundred fifteen million, five hundred six thousand, seven hundred twenty-nine".