78961 has 3 divisors (see below), whose sum is σ = 79243.
Its totient is φ = 78680.
The previous prime is 78941. The next prime is 78977. The reversal of 78961 is 16987.
78961 = T280 + T281.
The square root of 78961 is 281.
It is a perfect power (a square), and thus also a powerful number.
78961 is nontrivially palindromic in base 4.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It can be written as a sum of positive squares in only one way, i.e., 53361 + 25600 = 231^2 + 160^2
It is not a de Polignac number, because 78961 - 25 = 78929 is a prime.
It is an Ulam number.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
It is a zygodrome in base 3.
It is not an unprimeable number, because it can be changed into a prime (78901) by changing a digit.
It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 141 + ... + 421.
278961 is an apocalyptic number.
78961 is the 281-st square number.
78961 is the 141-st centered octagonal number.
It is an amenable number.
78961 is a deficient number, since it is larger than the sum of its proper divisors (282).
78961 is an frugal number, since it uses more digits than its factorization.
78961 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 562 (or 281 counting only the distinct ones).
The product of its digits is 3024, while the sum is 31.
The cubic root of 78961 is about 42.9013422314.
The spelling of 78961 in words is "seventy-eight thousand, nine hundred sixty-one".