81317077 has 2 divisors, whose sum is σ = 81317078. Its totient is φ = 81317076.

The previous prime is 81317057. The next prime is 81317129. The reversal of 81317077 is 77071318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77898276 + 3418801 = 8826^2 + 1849^2 .

It is a cyclic number.

It is not a de Polignac number, because 81317077 - 2¹⁵ = 81284309 is a prime.

It is a super-2 number, since 2×81317077² = 13224934023647858, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81317057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40658538 + 40658539.

It is an arithmetic number, because the mean of its divisors is an integer number (40658539).

Almost surely, 2^81317077 is an apocalyptic number.

It is an amenable number.

81317077 is a deficient number, since it is larger than the sum of its proper divisors (1).

81317077 is an equidigital number, since it uses as much as digits as its factorization.

81317077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8232, while the sum is 34.

The square root of 81317077 is about 9017.5981835520. The cubic root of 81317077 is about 433.2387090563.

The spelling of 81317077 in words is "eighty-one million, three hundred seventeen thousand, seventy-seven".