81764687 has 2 divisors, whose sum is σ = 81764688. Its totient is φ = 81764686.

The previous prime is 81764681. The next prime is 81764707. The reversal of 81764687 is 78646718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81764687 - 2⁶ = 81764623 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 (81764681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40882343 + 40882344.

It is an arithmetic number, because the mean of its divisors is an integer number (40882344).

Almost surely, 2^81764687 is an apocalyptic number.

81764687 is a deficient number, since it is larger than the sum of its proper divisors (1).

81764687 is an equidigital number, since it uses as much as digits as its factorization.

81764687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 47.

The square root of 81764687 is about 9042.3828164926. The cubic root of 81764687 is about 434.0321760425.

The spelling of 81764687 in words is "eighty-one million, seven hundred sixty-four thousand, six hundred eighty-seven".