1663456378 has 4 divisors (see below), whose sum is σ = 2495184570. Its totient is φ = 831728188.

The previous prime is 1663456343. The next prime is 1663456381. The reversal of 1663456378 is 8736543661.

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

It can be written as a sum of positive squares in only one way, i.e., 1198752129 + 464704249 = 34623^2 + 21557^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 415864093 + ... + 415864096.

Almost surely, 2^1663456378 is an apocalyptic number.

1663456378 is a deficient number, since it is larger than the sum of its proper divisors (831728192).

1663456378 is an equidigital number, since it uses as much as digits as its factorization.

1663456378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831728191.

The product of its digits is 2177280, while the sum is 49.

The square root of 1663456378 is about 40785.4922490829. The cubic root of 1663456378 is about 1184.8693685930.

The spelling of 1663456378 in words is "one billion, six hundred sixty-three million, four hundred fifty-six thousand, three hundred seventy-eight".