78329981 has 4 divisors (see below), whose sum is σ = 78348192. Its totient is φ = 78311772.

The previous prime is 78329971. The next prime is 78329983. The reversal of 78329981 is 18992387.

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: 18992387 = 547 ⋅34721.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78329981 is a prime.

It is a super-2 number, since 2×78329981² = 12271171846920722, 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 (78329983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1346 + ... + 12588.

It is an arithmetic number, because the mean of its divisors is an integer number (19587048).

Almost surely, 2^78329981 is an apocalyptic number.

It is an amenable number.

78329981 is a deficient number, since it is larger than the sum of its proper divisors (18211).

78329981 is a wasteful number, since it uses less digits than its factorization.

78329981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18210.

The product of its digits is 217728, while the sum is 47.

The square root of 78329981 is about 8850.4226452752. The cubic root of 78329981 is about 427.8675402397.

The spelling of 78329981 in words is "seventy-eight million, three hundred twenty-nine thousand, nine hundred eighty-one".