3781265681 has 4 divisors (see below), whose sum is σ = 4003693092. Its totient is φ = 3558838272.

The previous prime is 3781265599. The next prime is 3781265693. The reversal of 3781265681 is 1865621873.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1865621873 = 109 ⋅17115797.

It can be written as a sum of positive squares in 2 ways, for example, as 3505705681 + 275560000 = 59209^2 + 16600^2 .

It is a cyclic number.

It is not a de Polignac number, because 3781265681 - 2¹⁰ = 3781264657 is a prime.

It is a super-2 number, since 2×3781265681² = 28595940300616787522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3781261681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111213680 + ... + 111213713.

It is an arithmetic number, because the mean of its divisors is an integer number (1000923273).

Almost surely, 2^3781265681 is an apocalyptic number.

It is an amenable number.

3781265681 is a deficient number, since it is larger than the sum of its proper divisors (222427411).

3781265681 is a wasteful number, since it uses less digits than its factorization.

3781265681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222427410.

The product of its digits is 483840, while the sum is 47.

The square root of 3781265681 is about 61491.9968857737. The cubic root of 3781265681 is about 1557.9220746756.

The spelling of 3781265681 in words is "three billion, seven hundred eighty-one million, two hundred sixty-five thousand, six hundred eighty-one".