78986981 has 8 divisors (see below), whose sum is σ = 86517720. Its totient is φ = 71776768.

The previous prime is 78986969. The next prime is 78986989. The reversal of 78986981 is 18968987.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13942756 + 65044225 = 3734^2 + 8065^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 78986981 - 2⁶ = 78986917 is a prime.

It is a super-2 number, since 2×78986981² = 12477886334988722, 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 (78986989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79616 + ... + 80601.

It is an arithmetic number, because the mean of its divisors is an integer number (10814715).

Almost surely, 2^78986981 is an apocalyptic number.

It is an amenable number.

78986981 is a deficient number, since it is larger than the sum of its proper divisors (7530739).

78986981 is a wasteful number, since it uses less digits than its factorization.

78986981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160263.

The product of its digits is 1741824, while the sum is 56.

The square root of 78986981 is about 8887.4620111706. The cubic root of 78986981 is about 429.0604707531.

The spelling of 78986981 in words is "seventy-eight million, nine hundred eighty-six thousand, nine hundred eighty-one".