1685860261 has 4 divisors (see below), whose sum is σ = 1695605292. Its totient is φ = 1676115232.

The previous prime is 1685860217. The next prime is 1685860271. The reversal of 1685860261 is 1620685861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1620685861 = 11677 ⋅138793.

It can be written as a sum of positive squares in 2 ways, for example, as 944332900 + 741527361 = 30730^2 + 27231^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685860261 - 2⁷ = 1685860133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1685860271) 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 3 ways as a sum of consecutive naturals, for example, 4872256 + ... + 4872601.

It is an arithmetic number, because the mean of its divisors is an integer number (423901323).

Almost surely, 2^1685860261 is an apocalyptic number.

It is an amenable number.

1685860261 is a deficient number, since it is larger than the sum of its proper divisors (9745031).

1685860261 is an equidigital number, since it uses as much as digits as its factorization.

1685860261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9745030.

The product of its (nonzero) digits is 138240, while the sum is 43.

The square root of 1685860261 is about 41059.2286946552. The cubic root of 1685860261 is about 1190.1650457238.

The spelling of 1685860261 in words is "one billion, six hundred eighty-five million, eight hundred sixty thousand, two hundred sixty-one".