81712937 has 2 divisors, whose sum is σ = 81712938. Its totient is φ = 81712936.

The previous prime is 81712921. The next prime is 81712991. The reversal of 81712937 is 73921718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81522841 + 190096 = 9029^2 + 436^2 .

It is a cyclic number.

It is not a de Polignac number, because 81712937 - 2⁴ = 81712921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81712937.

It is not a weakly prime, because it can be changed into another prime (81718937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40856468 + 40856469.

It is an arithmetic number, because the mean of its divisors is an integer number (40856469).

Almost surely, 2^81712937 is an apocalyptic number.

It is an amenable number.

81712937 is a deficient number, since it is larger than the sum of its proper divisors (1).

81712937 is an equidigital number, since it uses as much as digits as its factorization.

81712937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 81712937 is about 9039.5208390711. The cubic root of 81712937 is about 433.9405883973.

The spelling of 81712937 in words is "eighty-one million, seven hundred twelve thousand, nine hundred thirty-seven".