1378663281 has 16 divisors (see below), whose sum is σ = 2043256000. Its totient is φ = 918752544.

The previous prime is 1378663261. The next prime is 1378663289. The reversal of 1378663281 is 1823668731.

1378663281 is a `hidden beast` number, since 1 + 3 + 7 + 8 + 6 + 632 + 8 + 1 = 666.

1378663281 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1378663281 - 2⁵ = 1378663249 is a prime.

It is a super-2 number, since 2×1378663281² = 3801424884755369922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1378663289) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73950 + ... + 90696.

It is an arithmetic number, because the mean of its divisors is an integer number (127703500).

Almost surely, 2^1378663281 is an apocalyptic number.

It is an amenable number.

1378663281 is a deficient number, since it is larger than the sum of its proper divisors (664592719).

1378663281 is a wasteful number, since it uses less digits than its factorization.

1378663281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19805 (or 19799 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 1378663281 is about 37130.3552501185. The cubic root of 1378663281 is about 1112.9766925031.

The spelling of 1378663281 in words is "one billion, three hundred seventy-eight million, six hundred sixty-three thousand, two hundred eighty-one".