1668996990 has 48 divisors (see below), whose sum is σ = 4343929200. Its totient is φ = 444600576.

The previous prime is 1668996961. The next prime is 1668997007. The reversal of 1668996990 is 996998661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81621 + ... + 99999.

It is an arithmetic number, because the mean of its divisors is an integer number (90498525).

Almost surely, 2^1668996990 is an apocalyptic number.

1668996990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1668996990 is an abundant number, since it is smaller than the sum of its proper divisors (2674932210).

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

1668996990 is a wasteful number, since it uses less digits than its factorization.

1668996990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19401 (or 19398 counting only the distinct ones).

The product of its (nonzero) digits is 11337408, while the sum is 63.

The square root of 1668996990 is about 40853.3595925721. The cubic root of 1668996990 is about 1186.1834249223.

It can be divided in two parts, 166899 and 6990, that added together give a square (173889 = 417²).

The spelling of 1668996990 in words is "one billion, six hundred sixty-eight million, nine hundred ninety-six thousand, nine hundred ninety".