381388816 has 10 divisors (see below), whose sum is σ = 738940862. Its totient is φ = 190694400.

The previous prime is 381388811. The next prime is 381388817. The reversal of 381388816 is 618883183.

It can be written as a sum of positive squares in only one way, i.e., 246364416 + 135024400 = 15696^2 + 11620^2 .

It is not an unprimeable number, because it can be changed into a prime (381388811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11918385 + ... + 11918416.

Almost surely, 2^381388816 is an apocalyptic number.

It is an amenable number.

381388816 is a deficient number, since it is larger than the sum of its proper divisors (357552046).

381388816 is a wasteful number, since it uses less digits than its factorization.

381388816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23836809 (or 23836803 counting only the distinct ones).

The product of its digits is 221184, while the sum is 46.

The square root of 381388816 is about 19529.1785797560. The cubic root of 381388816 is about 725.1969760465.

It can be divided in two parts, 3813 and 88816, that added together give a palindrome (92629).

The spelling of 381388816 in words is "three hundred eighty-one million, three hundred eighty-eight thousand, eight hundred sixteen".