1720687985 has 8 divisors (see below), whose sum is σ = 2070778176. Its totient is φ = 1372582000.

The previous prime is 1720687981. The next prime is 1720687987. The reversal of 1720687985 is 5897860271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1720687985 - 2² = 1720687981 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720687981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 494141 + ... + 497610.

It is an arithmetic number, because the mean of its divisors is an integer number (258847272).

Almost surely, 2^1720687985 is an apocalyptic number.

It is an amenable number.

1720687985 is a deficient number, since it is larger than the sum of its proper divisors (350090191).

1720687985 is an equidigital number, since it uses as much as digits as its factorization.

1720687985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 992103.

The product of its (nonzero) digits is 1693440, while the sum is 53.

The square root of 1720687985 is about 41481.1762731001. The cubic root of 1720687985 is about 1198.3050109057.

The spelling of 1720687985 in words is "one billion, seven hundred twenty million, six hundred eighty-seven thousand, nine hundred eighty-five".