81216763 has 2 divisors, whose sum is σ = 81216764. Its totient is φ = 81216762.

The previous prime is 81216761. The next prime is 81216781. The reversal of 81216763 is 36761218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81216763 - 2¹ = 81216761 is a prime.

Together with 81216761, it forms a pair of twin primes.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81216761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40608381 + 40608382.

It is an arithmetic number, because the mean of its divisors is an integer number (40608382).

Almost surely, 2^81216763 is an apocalyptic number.

81216763 is a deficient number, since it is larger than the sum of its proper divisors (1).

81216763 is an equidigital number, since it uses as much as digits as its factorization.

81216763 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 81216763 is about 9012.0343430327. The cubic root of 81216763 is about 433.0604857660.

It can be divided in two parts, 8121 and 6763, that added together give a square (14884 = 122²).

The spelling of 81216763 in words is "eighty-one million, two hundred sixteen thousand, seven hundred sixty-three".