81907777739 has 2 divisors, whose sum is σ = 81907777740. Its totient is φ = 81907777738.

The previous prime is 81907777733. The next prime is 81907777759. The reversal of 81907777739 is 93777770918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81907777739 - 2⁴ = 81907777723 is a prime.

It is not a weakly prime, because it can be changed into another prime (81907777733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40953888869 + 40953888870.

It is an arithmetic number, because the mean of its divisors is an integer number (40953888870).

Almost surely, 2^81907777739 is an apocalyptic number.

81907777739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81907777739 is an equidigital number, since it uses as much as digits as its factorization.

81907777739 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32672808, while the sum is 65.

The spelling of 81907777739 in words is "eighty-one billion, nine hundred seven million, seven hundred seventy-seven thousand, seven hundred thirty-nine".