378690821 has 2 divisors, whose sum is σ = 378690822. Its totient is φ = 378690820.

The previous prime is 378690799. The next prime is 378690839. The reversal of 378690821 is 128096873.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212022721 + 166668100 = 14561^2 + 12910^2 .

It is a cyclic number.

It is not a de Polignac number, because 378690821 - 2¹⁴ = 378674437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (378690841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 189345410 + 189345411.

It is an arithmetic number, because the mean of its divisors is an integer number (189345411).

Almost surely, 2^378690821 is an apocalyptic number.

It is an amenable number.

378690821 is a deficient number, since it is larger than the sum of its proper divisors (1).

378690821 is an equidigital number, since it uses as much as digits as its factorization.

378690821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 378690821 is about 19459.9799845735. The cubic root of 378690821 is about 723.4828812714.

The spelling of 378690821 in words is "three hundred seventy-eight million, six hundred ninety thousand, eight hundred twenty-one".