81370037321 has 2 divisors, whose sum is σ = 81370037322. Its totient is φ = 81370037320.

The previous prime is 81370037297. The next prime is 81370037347. The reversal of 81370037321 is 12373007318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45473430025 + 35896607296 = 213245^2 + 189464^2 .

It is a cyclic number.

It is not a de Polignac number, because 81370037321 - 2²⁶ = 81302928457 is a prime.

It is not a weakly prime, because it can be changed into another prime (81370033321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40685018660 + 40685018661.

It is an arithmetic number, because the mean of its divisors is an integer number (40685018661).

Almost surely, 2^81370037321 is an apocalyptic number.

It is an amenable number.

81370037321 is a deficient number, since it is larger than the sum of its proper divisors (1).

81370037321 is an equidigital number, since it uses as much as digits as its factorization.

81370037321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 35.

The spelling of 81370037321 in words is "eighty-one billion, three hundred seventy million, thirty-seven thousand, three hundred twenty-one".