378861781 has 2 divisors, whose sum is σ = 378861782. Its totient is φ = 378861780.

The previous prime is 378861761. The next prime is 378861793. The reversal of 378861781 is 187168873.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 359860900 + 19000881 = 18970^2 + 4359^2 .

It is a cyclic number.

It is not a de Polignac number, because 378861781 - 2¹⁹ = 378337493 is a prime.

It is a super-2 number, since 2×378861781² = 287072498204983922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (378861761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 189430890 + 189430891.

It is an arithmetic number, because the mean of its divisors is an integer number (189430891).

Almost surely, 2^378861781 is an apocalyptic number.

It is an amenable number.

378861781 is a deficient number, since it is larger than the sum of its proper divisors (1).

378861781 is an equidigital number, since it uses as much as digits as its factorization.

378861781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 49.

The square root of 378861781 is about 19464.3720936484. The cubic root of 378861781 is about 723.5917370260.

The spelling of 378861781 in words is "three hundred seventy-eight million, eight hundred sixty-one thousand, seven hundred eighty-one".