13778 has 6 divisors (see below), whose sum is σ = 20919.
Its totient is φ = 6806.
The previous prime is 13763. The next prime is 13781. The reversal of 13778 is 87731.
It can be written as a sum of positive squares in only one way, i.e., 6889 + 6889 = 83^2 + 83^2
It is an ABA number since it can be written as A⋅BA, here for A=2, B=83.
It is a Duffinian number.
Its product of digits (1176) is a multiple of the sum of its prime factors (168).
It is a plaindrome in base 10.
It is an unprimeable number.
13778 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 125 + ... + 207.
213778 is an apocalyptic number.
13778 is a deficient number, since it is larger than the sum of its proper divisors (7141).
13778 is an frugal number, since it uses more digits than its factorization.
13778 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 168 (or 85 counting only the distinct ones).
The product of its digits is 1176, while the sum is 26.
The square root of 13778 is about 117.3797256770.
The cubic root of 13778 is about 23.9733500481.
The spelling of 13778 in words is "thirteen thousand, seven hundred seventy-eight".