81296777 has 2 divisors, whose sum is σ = 81296778. Its totient is φ = 81296776.

The previous prime is 81296741. The next prime is 81296779. The reversal of 81296777 is 77769218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79138816 + 2157961 = 8896^2 + 1469^2 .

It is a cyclic number.

It is not a de Polignac number, because 81296777 - 2¹² = 81292681 is a prime.

Together with 81296779, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81296779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40648388 + 40648389.

It is an arithmetic number, because the mean of its divisors is an integer number (40648389).

Almost surely, 2^81296777 is an apocalyptic number.

It is an amenable number.

81296777 is a deficient number, since it is larger than the sum of its proper divisors (1).

81296777 is an equidigital number, since it uses as much as digits as its factorization.

81296777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 296352, while the sum is 47.

The square root of 81296777 is about 9016.4725364191. The cubic root of 81296777 is about 433.2026548101.

The spelling of 81296777 in words is "eighty-one million, two hundred ninety-six thousand, seven hundred seventy-seven".