81000077 has 2 divisors, whose sum is σ = 81000078. Its totient is φ = 81000076.

The previous prime is 81000071. The next prime is 81000083. The reversal of 81000077 is 77000018.

It is a balanced prime because it is at equal distance from previous prime (81000071) and next prime (81000083).

It can be written as a sum of positive squares in only one way, i.e., 42237001 + 38763076 = 6499^2 + 6226^2 .

It is a cyclic number.

It is not a de Polignac number, because 81000077 - 2⁴ = 81000061 is a prime.

It is a super-2 number, since 2×81000077² = 13122024948011858, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81000071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40500038 + 40500039.

It is an arithmetic number, because the mean of its divisors is an integer number (40500039).

Almost surely, 2^81000077 is an apocalyptic number.

It is an amenable number.

81000077 is a deficient number, since it is larger than the sum of its proper divisors (1).

81000077 is an equidigital number, since it uses as much as digits as its factorization.

81000077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 81000077 is about 9000.0042777768. The cubic root of 81000077 is about 432.6750081949.

The spelling of 81000077 in words is "eighty-one million, seventy-seven", and thus it is an aban number and an uban number.