378665909 has 4 divisors (see below), whose sum is σ = 378823104. Its totient is φ = 378508716.

The previous prime is 378665863. The next prime is 378665921. The reversal of 378665909 is 909566873.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 909566873 = 479 ⋅1898887.

It is a cyclic number.

It is not a de Polignac number, because 378665909 - 2¹⁶ = 378600373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (378665999) 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, 74927 + ... + 79820.

It is an arithmetic number, because the mean of its divisors is an integer number (94705776).

Almost surely, 2^378665909 is an apocalyptic number.

It is an amenable number.

378665909 is a deficient number, since it is larger than the sum of its proper divisors (157195).

378665909 is a wasteful number, since it uses less digits than its factorization.

378665909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157194.

The product of its (nonzero) digits is 2449440, while the sum is 53.

The square root of 378665909 is about 19459.3398911679. The cubic root of 378665909 is about 723.4670162616.

The spelling of 378665909 in words is "three hundred seventy-eight million, six hundred sixty-five thousand, nine hundred nine".