81066637 has 2 divisors, whose sum is σ = 81066638. Its totient is φ = 81066636.

The previous prime is 81066631. The next prime is 81066691. The reversal of 81066637 is 73666018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71419401 + 9647236 = 8451^2 + 3106^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81066637 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81066596 and 81066605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81066631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40533318 + 40533319.

It is an arithmetic number, because the mean of its divisors is an integer number (40533319).

Almost surely, 2^81066637 is an apocalyptic number.

It is an amenable number.

81066637 is a deficient number, since it is larger than the sum of its proper divisors (1).

81066637 is an equidigital number, since it uses as much as digits as its factorization.

81066637 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 81066637 is about 9003.7012944677. The cubic root of 81066637 is about 432.7934894151.

The spelling of 81066637 in words is "eighty-one million, sixty-six thousand, six hundred thirty-seven".