81078878 has 4 divisors (see below), whose sum is σ = 121618320. Its totient is φ = 40539438.

The previous prime is 81078863. The next prime is 81078883. The reversal of 81078878 is 87887018.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20269718 + ... + 20269721.

It is an arithmetic number, because the mean of its divisors is an integer number (30404580).

Almost surely, 2^81078878 is an apocalyptic number.

81078878 is a deficient number, since it is larger than the sum of its proper divisors (40539442).

81078878 is a wasteful number, since it uses less digits than its factorization.

81078878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40539441.

The product of its (nonzero) digits is 200704, while the sum is 47.

The square root of 81078878 is about 9004.3810448026. The cubic root of 81078878 is about 432.8152721470.

The spelling of 81078878 in words is "eighty-one million, seventy-eight thousand, eight hundred seventy-eight".