81216768 has 36 divisors (see below), whose sum is σ = 216157088. Its totient is φ = 27072000.

The previous prime is 81216763. The next prime is 81216781. The reversal of 81216768 is 86761218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81216761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52108 + ... + 53643.

Almost surely, 2^81216768 is an apocalyptic number.

It is an amenable number.

81216768 is an abundant number, since it is smaller than the sum of its proper divisors (134940320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81216768 is a wasteful number, since it uses less digits than its factorization.

81216768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105770 (or 105756 counting only the distinct ones).

The product of its digits is 32256, while the sum is 39.

The square root of 81216768 is about 9012.0346204395. The cubic root of 81216768 is about 433.0604946529.

The spelling of 81216768 in words is "eighty-one million, two hundred sixteen thousand, seven hundred sixty-eight".