72800380021 has 2 divisors, whose sum is σ = 72800380022. Its totient is φ = 72800380020.

The previous prime is 72800379989. The next prime is 72800380087. The reversal of 72800380021 is 12008300827.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58731099025 + 14069280996 = 242345^2 + 118614^2 .

It is a cyclic number.

It is not a de Polignac number, because 72800380021 - 2⁵ = 72800379989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72800380621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36400190010 + 36400190011.

It is an arithmetic number, because the mean of its divisors is an integer number (36400190011).

Almost surely, 2^72800380021 is an apocalyptic number.

It is an amenable number.

72800380021 is a deficient number, since it is larger than the sum of its proper divisors (1).

72800380021 is an equidigital number, since it uses as much as digits as its factorization.

72800380021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 31.

Adding to 72800380021 its reverse (12008300827), we get a palindrome (84808680848).

The spelling of 72800380021 in words is "seventy-two billion, eight hundred million, three hundred eighty thousand, twenty-one".