1664663878 has 32 divisors (see below), whose sum is σ = 2616999840. Its totient is φ = 793440000.

The previous prime is 1664663873. The next prime is 1664663881. The reversal of 1664663878 is 8783664661.

It is a super-2 number, since 2×1664663878² = 5542211653435997768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664663873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 874728 + ... + 876628.

It is an arithmetic number, because the mean of its divisors is an integer number (81781245).

Almost surely, 2^1664663878 is an apocalyptic number.

1664663878 is a deficient number, since it is larger than the sum of its proper divisors (952335962).

1664663878 is a wasteful number, since it uses less digits than its factorization.

1664663878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2184.

The product of its digits is 6967296, while the sum is 55.

The square root of 1664663878 is about 40800.2926214997. The cubic root of 1664663878 is about 1185.1559974326.

The spelling of 1664663878 in words is "one billion, six hundred sixty-four million, six hundred sixty-three thousand, eight hundred seventy-eight".