78866981 has 4 divisors (see below), whose sum is σ = 78959232. Its totient is φ = 78774732.

The previous prime is 78866971. The next prime is 78866989. The reversal of 78866981 is 18966887.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18966887 = 41 ⋅462607.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78866981 is a prime.

It is a super-2 number, since 2×78866981² = 12440001384108722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78866989) 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 3 ways as a sum of consecutive naturals, for example, 44831 + ... + 46556.

It is an arithmetic number, because the mean of its divisors is an integer number (19739808).

Almost surely, 2^78866981 is an apocalyptic number.

It is an amenable number.

78866981 is a deficient number, since it is larger than the sum of its proper divisors (92251).

78866981 is an equidigital number, since it uses as much as digits as its factorization.

78866981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92250.

The product of its digits is 1161216, while the sum is 53.

The square root of 78866981 is about 8880.7083613865. The cubic root of 78866981 is about 428.8430790105.

The spelling of 78866981 in words is "seventy-eight million, eight hundred sixty-six thousand, nine hundred eighty-one".