1668685990 has 8 divisors (see below), whose sum is σ = 3003634800. Its totient is φ = 667474392.

The previous prime is 1668685957. The next prime is 1668685999. The reversal of 1668685990 is 995868661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668685999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83434290 + ... + 83434309.

It is an arithmetic number, because the mean of its divisors is an integer number (375454350).

Almost surely, 2^1668685990 is an apocalyptic number.

1668685990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1668685990 is a deficient number, since it is larger than the sum of its proper divisors (1334948810).

1668685990 is a wasteful number, since it uses less digits than its factorization.

1668685990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166868606.

The product of its (nonzero) digits is 5598720, while the sum is 58.

The square root of 1668685990 is about 40849.5531187307. The cubic root of 1668685990 is about 1186.1097427520.

The spelling of 1668685990 in words is "one billion, six hundred sixty-eight million, six hundred eighty-five thousand, nine hundred ninety".