378185809 has 3 divisors (see below), whose sum is σ = 378205257. Its totient is φ = 378166362.

The previous prime is 378185789. The next prime is 378185813. The reversal of 378185809 is 908581873.

The square root of 378185809 is 19447.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 908581873 = 43 ⋅21129811.

It is not a de Polignac number, because 378185809 - 2⁵ = 378185777 is a prime.

It is a super-2 number, since 2×378185809² = 286049012257968962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (378185609) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 9724 + ... + 29170.

It is an arithmetic number, because the mean of its divisors is an integer number (126068419).

Almost surely, 2^378185809 is an apocalyptic number.

378185809 is the 19447-th square number.

378185809 is the 9724-th centered octagonal number.

It is an amenable number.

378185809 is a deficient number, since it is larger than the sum of its proper divisors (19448).

378185809 is an frugal number, since it uses more digits than its factorization.

378185809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38894 (or 19447 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 49.

The cubic root of 378185809 is about 723.1611323654.

Multiplying 378185809 by its sum of digits (49), we get a square (18531104641 = 136129²).

The spelling of 378185809 in words is "three hundred seventy-eight million, one hundred eighty-five thousand, eight hundred nine".