86821978 has 8 divisors (see below), whose sum is σ = 130282272. Its totient is φ = 43394556.

The previous prime is 86821967. The next prime is 86821991. The reversal of 86821978 is 87912868.

It is a sphenic number, since it is the product of 3 distinct primes.

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, 51 + ... + 13177.

It is an arithmetic number, because the mean of its divisors is an integer number (16285284).

Almost surely, 2^86821978 is an apocalyptic number.

86821978 is a deficient number, since it is larger than the sum of its proper divisors (43460294).

86821978 is a wasteful number, since it uses less digits than its factorization.

86821978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16436.

The product of its digits is 387072, while the sum is 49.

The square root of 86821978 is about 9317.8311854208. The cubic root of 86821978 is about 442.8023243875.

The spelling of 86821978 in words is "eighty-six million, eight hundred twenty-one thousand, nine hundred seventy-eight".