81787330687 has 2 divisors, whose sum is σ = 81787330688. Its totient is φ = 81787330686.

The previous prime is 81787330679. The next prime is 81787330717. The reversal of 81787330687 is 78603378718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81787330687 - 2³ = 81787330679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81787330607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40893665343 + 40893665344.

It is an arithmetic number, because the mean of its divisors is an integer number (40893665344).

Almost surely, 2^81787330687 is an apocalyptic number.

81787330687 is a deficient number, since it is larger than the sum of its proper divisors (1).

81787330687 is an equidigital number, since it uses as much as digits as its factorization.

81787330687 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9483264, while the sum is 58.

The spelling of 81787330687 in words is "eighty-one billion, seven hundred eighty-seven million, three hundred thirty thousand, six hundred eighty-seven".