1720380561 has 16 divisors (see below), whose sum is σ = 2347026624. Its totient is φ = 1120621824.

The previous prime is 1720380547. The next prime is 1720380643. The reversal of 1720380561 is 1650830271.

It is not a de Polignac number, because 1720380561 - 2¹³ = 1720372369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1720380521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13276 + ... + 60141.

It is an arithmetic number, because the mean of its divisors is an integer number (146689164).

Almost surely, 2^1720380561 is an apocalyptic number.

It is an amenable number.

1720380561 is a deficient number, since it is larger than the sum of its proper divisors (626646063).

1720380561 is a wasteful number, since it uses less digits than its factorization.

1720380561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73600.

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 1720380561 is about 41477.4705231647. The cubic root of 1720380561 is about 1198.2336422315.

The spelling of 1720380561 in words is "one billion, seven hundred twenty million, three hundred eighty thousand, five hundred sixty-one".