381781845 has 12 divisors (see below), whose sum is σ = 661755276. Its totient is φ = 203616960.

The previous prime is 381781831. The next prime is 381781847. The reversal of 381781845 is 548187183.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 93257649 + 288524196 = 9657^2 + 16986^2 .

It is not a de Polignac number, because 381781845 - 2¹⁵ = 381749077 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 8484041 = 381781845 / (3 + 8 + 1 + 7 + 8 + 1 + 8 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 381781845.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381781847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4241976 + ... + 4242065.

It is an arithmetic number, because the mean of its divisors is an integer number (55146273).

Almost surely, 2^381781845 is an apocalyptic number.

It is an amenable number.

381781845 is a deficient number, since it is larger than the sum of its proper divisors (279973431).

381781845 is a wasteful number, since it uses less digits than its factorization.

381781845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8484052 (or 8484049 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 381781845 is about 19539.2385982668. The cubic root of 381781845 is about 725.4460006454.

The spelling of 381781845 in words is "three hundred eighty-one million, seven hundred eighty-one thousand, eight hundred forty-five".