1681669820 has 12 divisors (see below), whose sum is σ = 3531506664. Its totient is φ = 672667920.

The previous prime is 1681669813. The next prime is 1681669853. The reversal of 1681669820 is 289661861.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42041726 + ... + 42041765.

It is an arithmetic number, because the mean of its divisors is an integer number (294292222).

Almost surely, 2^1681669820 is an apocalyptic number.

1681669820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1681669820 is an abundant number, since it is smaller than the sum of its proper divisors (1849836844).

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

1681669820 is a wasteful number, since it uses less digits than its factorization.

1681669820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84083500 (or 84083498 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 47.

The square root of 1681669820 is about 41008.1677230281. The cubic root of 1681669820 is about 1189.1781204411.

The spelling of 1681669820 in words is "one billion, six hundred eighty-one million, six hundred sixty-nine thousand, eight hundred twenty".