81243077 has 2 divisors, whose sum is σ = 81243078. Its totient is φ = 81243076.

The previous prime is 81243023. The next prime is 81243079. The reversal of 81243077 is 77034218.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51638596 + 29604481 = 7186^2 + 5441^2 .

It is a cyclic number.

It is not a de Polignac number, because 81243077 - 2⁶ = 81243013 is a prime.

Together with 81243079, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81243079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40621538 + 40621539.

It is an arithmetic number, because the mean of its divisors is an integer number (40621539).

Almost surely, 2^81243077 is an apocalyptic number.

It is an amenable number.

81243077 is a deficient number, since it is larger than the sum of its proper divisors (1).

81243077 is an equidigital number, since it uses as much as digits as its factorization.

81243077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 81243077 is about 9013.4941615336. The cubic root of 81243077 is about 433.1072508373.

The spelling of 81243077 in words is "eighty-one million, two hundred forty-three thousand, seventy-seven".