3780781 has 2 divisors, whose sum is σ = 3780782. Its totient is φ = 3780780.

The previous prime is 3780757. The next prime is 3780787. The reversal of 3780781 is 1870873.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3455881 + 324900 = 1859^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 3780781 - 2⁷ = 3780653 is a prime.

It is a super-2 number, since 2×3780781² = 28588609939922, which contains 22 as substring.

3780781 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3780787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1890390 + 1890391.

It is an arithmetic number, because the mean of its divisors is an integer number (1890391).

Almost surely, 2^3780781 is an apocalyptic number.

It is an amenable number.

3780781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3780781 is an equidigital number, since it uses as much as digits as its factorization.

3780781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 3780781 is about 1944.4230506760. The cubic root of 3780781 is about 155.7855507239.

The spelling of 3780781 in words is "three million, seven hundred eighty thousand, seven hundred eighty-one".