1681951681 has 8 divisors (see below), whose sum is σ = 1688331744. Its totient is φ = 1675581120.

The previous prime is 1681951673. The next prime is 1681951709. The reversal of 1681951681 is 1861591861.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1681951681 - 2³ = 1681951673 is a prime.

It is a super-2 number, since 2×1681951681² = 5657922914437451522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681951631) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 748746 + ... + 750988.

It is an arithmetic number, because the mean of its divisors is an integer number (211041468).

Almost surely, 2^1681951681 is an apocalyptic number.

It is an amenable number.

1681951681 is a deficient number, since it is larger than the sum of its proper divisors (6380063).

1681951681 is a wasteful number, since it uses less digits than its factorization.

1681951681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4751.

The product of its digits is 103680, while the sum is 46.

The square root of 1681951681 is about 41011.6042236828. The cubic root of 1681951681 is about 1189.2445552441.

The spelling of 1681951681 in words is "one billion, six hundred eighty-one million, nine hundred fifty-one thousand, six hundred eighty-one".