13781945 has 32 divisors (see below), whose sum is σ = 18385920. Its totient is φ = 9884160.

The previous prime is 13781941. The next prime is 13781947. The reversal of 13781945 is 54918731.

13781945 = 245² + 246² + ... + 382².

It is not a de Polignac number, because 13781945 - 2² = 13781941 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13781899 and 13781908.

It is not an unprimeable number, because it can be changed into a prime (13781941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 174416 + ... + 174494.

It is an arithmetic number, because the mean of its divisors is an integer number (574560).

Almost surely, 2^13781945 is an apocalyptic number.

It is an amenable number.

13781945 is a deficient number, since it is larger than the sum of its proper divisors (4603975).

13781945 is a wasteful number, since it uses less digits than its factorization.

13781945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185.

The product of its digits is 30240, while the sum is 38.

The square root of 13781945 is about 3712.4042075184. The cubic root of 13781945 is about 239.7563789443.

The spelling of 13781945 in words is "thirteen million, seven hundred eighty-one thousand, nine hundred forty-five".