81278916 has 12 divisors (see below), whose sum is σ = 189650832. Its totient is φ = 27092968.

The previous prime is 81278893. The next prime is 81278927. The reversal of 81278916 is 61987218.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×81278916² = 13212524372270112, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3386610 + ... + 3386633.

It is an arithmetic number, because the mean of its divisors is an integer number (15804236).

Almost surely, 2^81278916 is an apocalyptic number.

It is an amenable number.

81278916 is an abundant number, since it is smaller than the sum of its proper divisors (108371916).

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

81278916 is a wasteful number, since it uses less digits than its factorization.

81278916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6773250 (or 6773248 counting only the distinct ones).

The product of its digits is 48384, while the sum is 42.

The square root of 81278916 is about 9015.4820170638. The cubic root of 81278916 is about 433.1709274378.

The spelling of 81278916 in words is "eighty-one million, two hundred seventy-eight thousand, nine hundred sixteen".