1681000001 has 12 divisors (see below), whose sum is σ = 1798775628. Its totient is φ = 1570532352.

The previous prime is 1680999973. The next prime is 1681000019. The reversal of 1681000001 is 1000001861.

It is a happy number.

It is a Cunningham number, because it is equal to 41000²+1.

It can be written as a sum of positive squares in 6 ways, for example, as 521665600 + 1159334401 = 22840^2 + 34049^2 .

It is not a de Polignac number, because 1681000001 - 2³⁰ = 607258177 is a prime.

It is a super-2 number, since 2×1681000001² = 5651522006724000002, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681000301) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18365 + ... + 60821.

It is an arithmetic number, because the mean of its divisors is an integer number (149897969).

Almost surely, 2^1681000001 is an apocalyptic number.

It is an amenable number.

1681000001 is a deficient number, since it is larger than the sum of its proper divisors (117775627).

1681000001 is a wasteful number, since it uses less digits than its factorization.

1681000001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42628 (or 42611 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 1681000001 is about 41000.0000121951. Note that the first 4 decimals coincide. The cubic root of 1681000001 is about 1189.0202139230.

Adding to 1681000001 its reverse (1000001861), we get a palindrome (2681001862).

The spelling of 1681000001 in words is "one billion, six hundred eighty-one million, one", and thus it is an aban number.