81402077 has 2 divisors, whose sum is σ = 81402078. Its totient is φ = 81402076.

The previous prime is 81402067. The next prime is 81402089. The reversal of 81402077 is 77020418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73170916 + 8231161 = 8554^2 + 2869^2 .

It is a cyclic number.

It is not a de Polignac number, because 81402077 - 2¹⁰ = 81401053 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81402017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40701038 + 40701039.

It is an arithmetic number, because the mean of its divisors is an integer number (40701039).

Almost surely, 2^81402077 is an apocalyptic number.

It is an amenable number.

81402077 is a deficient number, since it is larger than the sum of its proper divisors (1).

81402077 is an equidigital number, since it uses as much as digits as its factorization.

81402077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 81402077 is about 9022.3099592067. The cubic root of 81402077 is about 433.3896099823.

The spelling of 81402077 in words is "eighty-one million, four hundred two thousand, seventy-seven".