20460136721 has 2 divisors, whose sum is σ = 20460136722. Its totient is φ = 20460136720.

The previous prime is 20460136691. The next prime is 20460136727. The reversal of 20460136721 is 12763106402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14795316496 + 5664820225 = 121636^2 + 75265^2 .

It is a cyclic number.

It is not a de Polignac number, because 20460136721 - 2¹⁴ = 20460120337 is a prime.

It is not a weakly prime, because it can be changed into another prime (20460136727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10230068360 + 10230068361.

It is an arithmetic number, because the mean of its divisors is an integer number (10230068361).

Almost surely, 2^20460136721 is an apocalyptic number.

It is an amenable number.

20460136721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20460136721 is an equidigital number, since it uses as much as digits as its factorization.

20460136721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 32.

The spelling of 20460136721 in words is "twenty billion, four hundred sixty million, one hundred thirty-six thousand, seven hundred twenty-one".