1681000020 has 192 divisors, whose sum is σ = 5997196800. Its totient is φ = 382924800.

The previous prime is 1681000019. The next prime is 1681000037. The reversal of 1681000020 is 200001861.

It is a super-2 number, since 2×1681000020² = 5651522134480000800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1680999957 and 1681000002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1515226 + ... + 1516334.

It is an arithmetic number, because the mean of its divisors is an integer number (31235400).

Almost surely, 2^1681000020 is an apocalyptic number.

1681000020 is a gapful number since it is divisible by the number (10) 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 1681000020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2998598400).

1681000020 is an abundant number, since it is smaller than the sum of its proper divisors (4316196780).

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

1681000020 is a wasteful number, since it uses less digits than its factorization.

1681000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535 (or 1527 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 1681000020 is about 41000.0002439024. Note that the first 3 decimals coincide. The cubic root of 1681000020 is about 1189.0202184028.

Adding to 1681000020 its reverse (200001861), we get a palindrome (1881001881).

The spelling of 1681000020 in words is "one billion, six hundred eighty-one million, twenty", and thus it is an aban number.