81788677 has 2 divisors, whose sum is σ = 81788678. Its totient is φ = 81788676.

The previous prime is 81788657. The next prime is 81788701. The reversal of 81788677 is 77688718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64224196 + 17564481 = 8014^2 + 4191^2 .

It is a cyclic number.

It is not a de Polignac number, because 81788677 - 2¹⁵ = 81755909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81788627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40894338 + 40894339.

It is an arithmetic number, because the mean of its divisors is an integer number (40894339).

Almost surely, 2^81788677 is an apocalyptic number.

It is an amenable number.

81788677 is a deficient number, since it is larger than the sum of its proper divisors (1).

81788677 is an equidigital number, since it uses as much as digits as its factorization.

81788677 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1053696, while the sum is 52.

The square root of 81788677 is about 9043.7092500810. The cubic root of 81788677 is about 434.0746206646.

The spelling of 81788677 in words is "eighty-one million, seven hundred eighty-eight thousand, six hundred seventy-seven".