78401 has 2 divisors, whose sum is σ = 78402. Its totient is φ = 78400.
The previous prime is 78367. The next prime is 78427. The reversal of 78401 is 10487.
It is a happy number.
It is a Cunningham number, because it is equal to 2802+1.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 78400 + 1 = 280^2 + 1^2 .
It is an emirp because it is prime and its reverse (10487) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 78401 - 210 = 77377 is a prime.
It is a super-2 number, since 2×784012 = 12293433602, which contains 22 as substring.
It is not a weakly prime, because it can be changed into another prime (78101) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39200 + 39201.
It is an arithmetic number, because the mean of its divisors is an integer number (39201).
278401 is an apocalyptic number.
It is an amenable number.
78401 is a deficient number, since it is larger than the sum of its proper divisors (1).
78401 is an equidigital number, since it uses as much as digits as its factorization.
78401 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 224, while the sum is 20.
The square root of 78401 is about 280.0017857086. The cubic root of 78401 is about 42.7996811925.
Adding to 78401 its reverse (10487), we get a palindrome (88888).
The spelling of 78401 in words is "seventy-eight thousand, four hundred one".
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