78243981 has 8 divisors (see below), whose sum is σ = 104439264. Its totient is φ = 52105680.

The previous prime is 78243967. The next prime is 78244021. The reversal of 78243981 is 18934287.

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

It is not a de Polignac number, because 78243981 - 2¹⁸ = 77981837 is a prime.

It is a super-2 number, since 2×78243981² = 12244241125456722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78243931) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10930 + ... + 16611.

It is an arithmetic number, because the mean of its divisors is an integer number (13054908).

Almost surely, 2^78243981 is an apocalyptic number.

It is an amenable number.

78243981 is a deficient number, since it is larger than the sum of its proper divisors (26195283).

78243981 is a wasteful number, since it uses less digits than its factorization.

78243981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28491.

The product of its digits is 96768, while the sum is 42.

The square root of 78243981 is about 8845.5627859396. The cubic root of 78243981 is about 427.7108948838.

The spelling of 78243981 in words is "seventy-eight million, two hundred forty-three thousand, nine hundred eighty-one".