81200137 has 2 divisors, whose sum is σ = 81200138. Its totient is φ = 81200136.

The previous prime is 81200113. The next prime is 81200173. The reversal of 81200137 is 73100218.

Together with next prime (81200173) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56310016 + 24890121 = 7504^2 + 4989^2 .

It is a cyclic number.

It is not a de Polignac number, because 81200137 - 2¹⁹ = 80675849 is a prime.

It is not a weakly prime, because it can be changed into another prime (81200437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40600068 + 40600069.

It is an arithmetic number, because the mean of its divisors is an integer number (40600069).

Almost surely, 2^81200137 is an apocalyptic number.

It is an amenable number.

81200137 is a deficient number, since it is larger than the sum of its proper divisors (1).

81200137 is an equidigital number, since it uses as much as digits as its factorization.

81200137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 81200137 is about 9011.1118625839. Note that the first 3 decimals coincide. The cubic root of 81200137 is about 433.0309329383.

The spelling of 81200137 in words is "eighty-one million, two hundred thousand, one hundred thirty-seven".