81437129 has 2 divisors, whose sum is σ = 81437130. Its totient is φ = 81437128.

The previous prime is 81437117. The next prime is 81437131. The reversal of 81437129 is 92173418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81360400 + 76729 = 9020^2 + 277^2 .

It is a cyclic number.

It is not a de Polignac number, because 81437129 - 2⁴ = 81437113 is a prime.

Together with 81437131, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81437159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40718564 + 40718565.

It is an arithmetic number, because the mean of its divisors is an integer number (40718565).

Almost surely, 2^81437129 is an apocalyptic number.

It is an amenable number.

81437129 is a deficient number, since it is larger than the sum of its proper divisors (1).

81437129 is an equidigital number, since it uses as much as digits as its factorization.

81437129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 35.

The square root of 81437129 is about 9024.2522681937. The cubic root of 81437129 is about 433.4518073825.

The spelling of 81437129 in words is "eighty-one million, four hundred thirty-seven thousand, one hundred twenty-nine".