80000000021 has 2 divisors, whose sum is σ = 80000000022. Its totient is φ = 80000000020.

The previous prime is 79999999999. The next prime is 80000000051. The reversal of 80000000021 is 12000000008.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77768476900 + 2231523121 = 278870^2 + 47239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80000000021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80000000051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40000000010 + 40000000011.

It is an arithmetic number, because the mean of its divisors is an integer number (40000000011).

Almost surely, 2^80000000021 is an apocalyptic number.

It is an amenable number.

80000000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

80000000021 is an equidigital number, since it uses as much as digits as its factorization.

80000000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 80000000021 its reverse (12000000008), we get a palindrome (92000000029).

The spelling of 80000000021 in words is "eighty billion, twenty-one", and thus it is an aban number and an uban number.