13778945 has 4 divisors (see below), whose sum is σ = 16534740. Its totient is φ = 11023152.

The previous prime is 13778929. The next prime is 13778951. The reversal of 13778945 is 54987731.

It is a Cunningham number, because it is equal to 3712²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4963984 + 8814961 = 2228^2 + 2969^2 .

It is a cyclic number.

It is not a de Polignac number, because 13778945 - 2⁴ = 13778929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13778896 and 13778905.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1377890 + ... + 1377899.

It is an arithmetic number, because the mean of its divisors is an integer number (4133685).

It is a Proth number, since it is equal to 841 ⋅ 2¹⁴ + 1 and 841 < 2¹⁴.

Almost surely, 2^13778945 is an apocalyptic number.

It is an amenable number.

13778945 is a deficient number, since it is larger than the sum of its proper divisors (2755795).

13778945 is an equidigital number, since it uses as much as digits as its factorization.

13778945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2755794.

The product of its digits is 211680, while the sum is 44.

The square root of 13778945 is about 3712.0001346983. Note that the first 3 decimals coincide. The cubic root of 13778945 is about 239.7389812710.

The spelling of 13778945 in words is "thirteen million, seven hundred seventy-eight thousand, nine hundred forty-five".