1681910691 has 16 divisors (see below), whose sum is σ = 2380412448. Its totient is φ = 1052672000.

The previous prime is 1681910663. The next prime is 1681910701. The reversal of 1681910691 is 1960191861.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1681910691 - 2⁷ = 1681910563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1681912691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20670 + ... + 61571.

It is an arithmetic number, because the mean of its divisors is an integer number (148775778).

Almost surely, 2^1681910691 is an apocalyptic number.

1681910691 is a deficient number, since it is larger than the sum of its proper divisors (698501757).

1681910691 is a wasteful number, since it uses less digits than its factorization.

1681910691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82662.

The product of its (nonzero) digits is 23328, while the sum is 42.

The square root of 1681910691 is about 41011.1044840297. The cubic root of 1681910691 is about 1189.2348943383.

The spelling of 1681910691 in words is "one billion, six hundred eighty-one million, nine hundred ten thousand, six hundred ninety-one".