20008200721 has 2 divisors, whose sum is σ = 20008200722. Its totient is φ = 20008200720.

The previous prime is 20008200691. The next prime is 20008200763. The reversal of 20008200721 is 12700280002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19666135696 + 342065025 = 140236^2 + 18495^2 .

It is a cyclic number.

It is not a de Polignac number, because 20008200721 - 2¹⁵ = 20008167953 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20008200692 and 20008200701.

It is not a weakly prime, because it can be changed into another prime (20008200221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10004100360 + 10004100361.

It is an arithmetic number, because the mean of its divisors is an integer number (10004100361).

Almost surely, 2^20008200721 is an apocalyptic number.

It is an amenable number.

20008200721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20008200721 is an equidigital number, since it uses as much as digits as its factorization.

20008200721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 22.

Adding to 20008200721 its reverse (12700280002), we get a palindrome (32708480723).

The spelling of 20008200721 in words is "twenty billion, eight million, two hundred thousand, seven hundred twenty-one".