1664778870 has 144 divisors (see below), whose sum is σ = 4596359040. Its totient is φ = 417947904.

The previous prime is 1664778811. The next prime is 1664778887. The reversal of 1664778870 is 788774661.

1664778870 is a `hidden beast` number, since 166 + 477 + 8 + 8 + 7 + 0 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3475291 + ... + 3475769.

It is an arithmetic number, because the mean of its divisors is an integer number (31919160).

Almost surely, 2^1664778870 is an apocalyptic number.

1664778870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1664778870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2298179520).

1664778870 is an abundant number, since it is smaller than the sum of its proper divisors (2931580170).

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

1664778870 is a wasteful number, since it uses less digits than its factorization.

1664778870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611 (or 585 counting only the distinct ones).

The product of its (nonzero) digits is 3161088, while the sum is 54.

The square root of 1664778870 is about 40801.7018027435. The cubic root of 1664778870 is about 1185.1832862890.

The spelling of 1664778870 in words is "one billion, six hundred sixty-four million, seven hundred seventy-eight thousand, eight hundred seventy".