1681051681 has 4 divisors (see below), whose sum is σ = 1779937092. Its totient is φ = 1582166272.

The previous prime is 1681051651. The next prime is 1681051699. The reversal of 1681051681 is 1861501861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1861501861 = 59 ⋅31550879.

It can be written as a sum of positive squares in 2 ways, for example, as 875627281 + 805424400 = 29591^2 + 28380^2 .

It is a cyclic number.

It is not a de Polignac number, because 1681051681 - 2¹¹ = 1681049633 is a prime.

It is a super-2 number, since 2×1681051681² = 5651869508385851522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1681051681.

It is not an unprimeable number, because it can be changed into a prime (1681051651) 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 3 ways as a sum of consecutive naturals, for example, 49442680 + ... + 49442713.

It is an arithmetic number, because the mean of its divisors is an integer number (444984273).

Almost surely, 2^1681051681 is an apocalyptic number.

It is an amenable number.

1681051681 is a deficient number, since it is larger than the sum of its proper divisors (98885411).

1681051681 is an equidigital number, since it uses as much as digits as its factorization.

1681051681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98885410.

The product of its (nonzero) digits is 11520, while the sum is 37.

The square root of 1681051681 is about 41000.6302512535. The cubic root of 1681051681 is about 1189.0323987208.

The spelling of 1681051681 in words is "one billion, six hundred eighty-one million, fifty-one thousand, six hundred eighty-one".