378655991 has 4 divisors (see below), whose sum is σ = 432749712. Its totient is φ = 324562272.

The previous prime is 378655973. The next prime is 378656029. The reversal of 378655991 is 199556873.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-378655991 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 (378655091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27046850 + ... + 27046863.

It is an arithmetic number, because the mean of its divisors is an integer number (108187428).

Almost surely, 2^378655991 is an apocalyptic number.

378655991 is a deficient number, since it is larger than the sum of its proper divisors (54093721).

378655991 is an equidigital number, since it uses as much as digits as its factorization.

378655991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54093720.

The product of its digits is 2041200, while the sum is 53.

The square root of 378655991 is about 19459.0850504334. The cubic root of 378655991 is about 723.4606998682.

The spelling of 378655991 in words is "three hundred seventy-eight million, six hundred fifty-five thousand, nine hundred ninety-one".