81629137 has 2 divisors, whose sum is σ = 81629138. Its totient is φ = 81629136.

The previous prime is 81629129. The next prime is 81629147. The reversal of 81629137 is 73192618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46771921 + 34857216 = 6839^2 + 5904^2 .

81629137 is a truncatable prime.

It is a cyclic number.

It is not a de Polignac number, because 81629137 - 2³ = 81629129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81629096 and 81629105.

It is not a weakly prime, because it can be changed into another prime (81629147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40814568 + 40814569.

It is an arithmetic number, because the mean of its divisors is an integer number (40814569).

Almost surely, 2^81629137 is an apocalyptic number.

It is an amenable number.

81629137 is a deficient number, since it is larger than the sum of its proper divisors (1).

81629137 is an equidigital number, since it uses as much as digits as its factorization.

81629137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 37.

The square root of 81629137 is about 9034.8844486247. The cubic root of 81629137 is about 433.7921963118.

The spelling of 81629137 in words is "eighty-one million, six hundred twenty-nine thousand, one hundred thirty-seven".