81707878 has 32 divisors (see below), whose sum is σ = 146626560. Its totient is φ = 33410880.

The previous prime is 81707867. The next prime is 81707881. The reversal of 81707878 is 87870718.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30393 + ... + 32971.

It is an arithmetic number, because the mean of its divisors is an integer number (4582080).

Almost surely, 2^81707878 is an apocalyptic number.

81707878 is a deficient number, since it is larger than the sum of its proper divisors (64918682).

81707878 is a wasteful number, since it uses less digits than its factorization.

81707878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2692.

The product of its (nonzero) digits is 175616, while the sum is 46.

The square root of 81707878 is about 9039.2410079608. The cubic root of 81707878 is about 433.9316328560.

The spelling of 81707878 in words is "eighty-one million, seven hundred seven thousand, eight hundred seventy-eight".