81278568 has 48 divisors (see below), whose sum is σ = 251578080. Its totient is φ = 23222304.

The previous prime is 81278551. The next prime is 81278579. The reversal of 81278568 is 86587218.

81278568 is a `hidden beast` number, since 8 + 12 + 78 + 568 = 666.

It is a super-2 number, since 2×81278568² = 13212411232261248, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80130 + ... + 81137.

It is an arithmetic number, because the mean of its divisors is an integer number (5241210).

Almost surely, 2^81278568 is an apocalyptic number.

It is an amenable number.

81278568 is an abundant number, since it is smaller than the sum of its proper divisors (170299512).

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

81278568 is a wasteful number, since it uses less digits than its factorization.

81278568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161286 (or 161279 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 81278568 is about 9015.4627169103. The cubic root of 81278568 is about 433.1703092222.

The spelling of 81278568 in words is "eighty-one million, two hundred seventy-eight thousand, five hundred sixty-eight".