1720381685 has 16 divisors (see below), whose sum is σ = 2253042432. Its totient is φ = 1250683200.

The previous prime is 1720381681. The next prime is 1720381697. The reversal of 1720381685 is 5861830271.

It is not a de Polignac number, because 1720381685 - 2² = 1720381681 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 (1720381681) 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 15 ways as a sum of consecutive naturals, for example, 182795 + ... + 191975.

It is an arithmetic number, because the mean of its divisors is an integer number (140815152).

Almost surely, 2^1720381685 is an apocalyptic number.

It is an amenable number.

1720381685 is a deficient number, since it is larger than the sum of its proper divisors (532660747).

1720381685 is a wasteful number, since it uses less digits than its factorization.

1720381685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12604.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 1720381685 is about 41477.4840726870. The cubic root of 1720381685 is about 1198.2339031843.

The spelling of 1720381685 in words is "one billion, seven hundred twenty million, three hundred eighty-one thousand, six hundred eighty-five".