1680731 has 4 divisors (see below), whose sum is σ = 1810032. Its totient is φ = 1551432.

The previous prime is 1680709. The next prime is 1680743. The reversal of 1680731 is 1370861.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1680731 is a prime.

It is a super-2 number, since 2×1680731² = 5649713388722, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1680731.

It is not an unprimeable number, because it can be changed into a prime (1680761) 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, 64631 + ... + 64656.

It is an arithmetic number, because the mean of its divisors is an integer number (452508).

2^1680731 is an apocalyptic number.

1680731 is a deficient number, since it is larger than the sum of its proper divisors (129301).

1680731 is a wasteful number, since it uses less digits than its factorization.

1680731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129300.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 1680731 is about 1296.4300983856. The cubic root of 1680731 is about 118.8956786461.

The spelling of 1680731 in words is "one million, six hundred eighty thousand, seven hundred thirty-one".