1666653678 has 64 divisors (see below), whose sum is σ = 3852288000. Its totient is φ = 533643552.

The previous prime is 1666653673. The next prime is 1666653679. The reversal of 1666653678 is 8763566661.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666653671) 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 in 31 ways as a sum of consecutive naturals, for example, 152563 + ... + 163121.

It is an arithmetic number, because the mean of its divisors is an integer number (60192000).

Almost surely, 2^1666653678 is an apocalyptic number.

1666653678 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666653678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1926144000).

1666653678 is an abundant number, since it is smaller than the sum of its proper divisors (2185634322).

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

1666653678 is a wasteful number, since it uses less digits than its factorization.

1666653678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10686 (or 10680 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The square root of 1666653678 is about 40824.6699680475. The cubic root of 1666653678 is about 1185.6280215353.

The spelling of 1666653678 in words is "one billion, six hundred sixty-six million, six hundred fifty-three thousand, six hundred seventy-eight".