1665441778 has 32 divisors (see below), whose sum is σ = 3354180480. Its totient is φ = 598959360.

The previous prime is 1665441749. The next prime is 1665441809. The reversal of 1665441778 is 8771445661.

It is a happy number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 413943 + ... + 417946.

It is an arithmetic number, because the mean of its divisors is an integer number (104818140).

Almost surely, 2^1665441778 is an apocalyptic number.

1665441778 is an abundant number, since it is smaller than the sum of its proper divisors (1688738702).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1665441778 is a wasteful number, since it uses less digits than its factorization.

1665441778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831922.

The product of its digits is 1128960, while the sum is 49.

The square root of 1665441778 is about 40809.8245279246. The cubic root of 1665441778 is about 1185.3405770932.

The spelling of 1665441778 in words is "one billion, six hundred sixty-five million, four hundred forty-one thousand, seven hundred seventy-eight".