81664463 has 2 divisors, whose sum is σ = 81664464. Its totient is φ = 81664462.

The previous prime is 81664441. The next prime is 81664507. The reversal of 81664463 is 36446618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81664463 - 2⁶ = 81664399 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 (81664423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40832231 + 40832232.

It is an arithmetic number, because the mean of its divisors is an integer number (40832232).

Almost surely, 2^81664463 is an apocalyptic number.

81664463 is a deficient number, since it is larger than the sum of its proper divisors (1).

81664463 is an equidigital number, since it uses as much as digits as its factorization.

81664463 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 38.

The square root of 81664463 is about 9036.8392151238. The cubic root of 81664463 is about 433.8547635668.

The spelling of 81664463 in words is "eighty-one million, six hundred sixty-four thousand, four hundred sixty-three".