1691444681 has 16 divisors (see below), whose sum is σ = 1744137984. Its totient is φ = 1639782144.

The previous prime is 1691444663. The next prime is 1691444683. The reversal of 1691444681 is 1864441961.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691444681 is a prime.

It is a super-3 number, since 3×1691444681³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1691444683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1187936 + ... + 1189358.

It is an arithmetic number, because the mean of its divisors is an integer number (109008624).

Almost surely, 2^1691444681 is an apocalyptic number.

It is an amenable number.

1691444681 is a deficient number, since it is larger than the sum of its proper divisors (52693303).

1691444681 is a wasteful number, since it uses less digits than its factorization.

1691444681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760.

The product of its digits is 165888, while the sum is 44.

The square root of 1691444681 is about 41127.1769150279. The cubic root of 1691444681 is about 1191.4777397809.

The spelling of 1691444681 in words is "one billion, six hundred ninety-one million, four hundred forty-four thousand, six hundred eighty-one".