1320631778 has 4 divisors (see below), whose sum is σ = 1980947670. Its totient is φ = 660315888.

The previous prime is 1320631777. The next prime is 1320631789. The reversal of 1320631778 is 8771360231.

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., 1255780969 + 64850809 = 35437^2 + 8053^2 .

It is not an unprimeable number, because it can be changed into a prime (1320631777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330157943 + ... + 330157946.

Almost surely, 2^1320631778 is an apocalyptic number.

1320631778 is a deficient number, since it is larger than the sum of its proper divisors (660315892).

1320631778 is an equidigital number, since it uses as much as digits as its factorization.

1320631778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660315891.

The product of its (nonzero) digits is 42336, while the sum is 38.

The square root of 1320631778 is about 36340.4977676421. The cubic root of 1320631778 is about 1097.1362916697.

The spelling of 1320631778 in words is "one billion, three hundred twenty million, six hundred thirty-one thousand, seven hundred seventy-eight".