3728781728449 has 2 divisors, whose sum is σ = 3728781728450. Its totient is φ = 3728781728448.

The previous prime is 3728781728431. The next prime is 3728781728471. The reversal of 3728781728449 is 9448271878273.

3728781728449 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2660917837824 + 1067863890625 = 1631232^2 + 1033375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3728781728449 is a prime.

It is a super-2 number, since 2×3728781728449² (a number of 26 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3728781728489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1864390864224 + 1864390864225.

It is an arithmetic number, because the mean of its divisors is an integer number (1864390864225).

Almost surely, 2^{3728781728449} is an apocalyptic number.

It is an amenable number.

3728781728449 is a deficient number, since it is larger than the sum of its proper divisors (1).

3728781728449 is an equidigital number, since it uses as much as digits as its factorization.

3728781728449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 303464448, while the sum is 70.

The spelling of 3728781728449 in words is "three trillion, seven hundred twenty-eight billion, seven hundred eighty-one million, seven hundred twenty-eight thousand, four hundred forty-nine".