1685809957 has 8 divisors (see below), whose sum is σ = 1817301080. Its totient is φ = 1554577920.

The previous prime is 1685809907. The next prime is 1685810003. The reversal of 1685809957 is 7599085861.

It can be written as a sum of positive squares in 4 ways, for example, as 30459361 + 1655350596 = 5519^2 + 40686^2 .

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 1685809957 - 2¹¹ = 1685807909 is a prime.

It is a super-2 number, since 2×1685809957² = 5683910422240683698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1685809907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51144 + ... + 77377.

It is an arithmetic number, because the mean of its divisors is an integer number (227162635).

Almost surely, 2^1685809957 is an apocalyptic number.

It is an amenable number.

1685809957 is a deficient number, since it is larger than the sum of its proper divisors (131491123).

1685809957 is a wasteful number, since it uses less digits than its factorization.

1685809957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129543.

The product of its (nonzero) digits is 5443200, while the sum is 58.

The square root of 1685809957 is about 41058.6161116032. The cubic root of 1685809957 is about 1190.1532079182.

The spelling of 1685809957 in words is "one billion, six hundred eighty-five million, eight hundred nine thousand, nine hundred fifty-seven".