1660821768 has 96 divisors (see below), whose sum is σ = 4850445600. Its totient is φ = 511660800.

The previous prime is 1660821763. The next prime is 1660821769. The reversal of 1660821768 is 8671280661.

It is a happy number.

1660821768 is a `hidden beast` number, since 16 + 608 + 21 + 7 + 6 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (1660821761) 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 23 ways as a sum of consecutive naturals, for example, 41283 + ... + 70893.

It is an arithmetic number, because the mean of its divisors is an integer number (50525475).

Almost surely, 2^1660821768 is an apocalyptic number.

1660821768 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1660821768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2425222800).

1660821768 is an abundant number, since it is smaller than the sum of its proper divisors (3189623832).

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

1660821768 is a wasteful number, since it uses less digits than its factorization.

1660821768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29683 (or 29676 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 1660821768 is about 40753.1810782913. The cubic root of 1660821768 is about 1184.2434994228.

The spelling of 1660821768 in words is "one billion, six hundred sixty million, eight hundred twenty-one thousand, seven hundred sixty-eight".