81978046 has 24 divisors (see below), whose sum is σ = 137434320. Its totient is φ = 36542016.

The previous prime is 81978023. The next prime is 81978053. The reversal of 81978046 is 64087918.

It is a junction number, because it is equal to n+sod(n) for n = 81977993 and 81978011.

It is a congruent number.

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, 8935 + ... + 15613.

It is an arithmetic number, because the mean of its divisors is an integer number (5726430).

Almost surely, 2^81978046 is an apocalyptic number.

81978046 is a deficient number, since it is larger than the sum of its proper divisors (55456274).

81978046 is a wasteful number, since it uses less digits than its factorization.

81978046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6736 (or 6717 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 81978046 is about 9054.1728501283. The cubic root of 81978046 is about 434.4093732680.

The spelling of 81978046 in words is "eighty-one million, nine hundred seventy-eight thousand, forty-six".