1686740240 has 20 divisors (see below), whose sum is σ = 3921671244. Its totient is φ = 674696064.

The previous prime is 1686740233. The next prime is 1686740249. The reversal of 1686740240 is 420476861.

It can be written as a sum of positive squares in 2 ways, for example, as 925863184 + 760877056 = 30428^2 + 27584^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1686740194 and 1686740203.

It is not an unprimeable number, because it can be changed into a prime (1686740249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10542047 + ... + 10542206.

Almost surely, 2^1686740240 is an apocalyptic number.

1686740240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1686740240 is an abundant number, since it is smaller than the sum of its proper divisors (2234931004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1686740240 is a wasteful number, since it uses less digits than its factorization.

1686740240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21084266 (or 21084260 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 1686740240 is about 41069.9432675527. The cubic root of 1686740240 is about 1190.3720889959.

The spelling of 1686740240 in words is "one billion, six hundred eighty-six million, seven hundred forty thousand, two hundred forty".