1720128923 has 4 divisors (see below), whose sum is σ = 1720346088. Its totient is φ = 1719911760.

The previous prime is 1720128913. The next prime is 1720128929. The reversal of 1720128923 is 3298210271.

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

It is a cyclic number.

It is not a de Polignac number, because 1720128923 - 2¹⁴ = 1720112539 is a prime.

It is a super-2 number, since 2×1720128923² = 5917687023482279858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720128929) 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, 96233 + ... + 112698.

It is an arithmetic number, because the mean of its divisors is an integer number (430086522).

Almost surely, 2^1720128923 is an apocalyptic number.

1720128923 is a deficient number, since it is larger than the sum of its proper divisors (217165).

1720128923 is an equidigital number, since it uses as much as digits as its factorization.

1720128923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217164.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 1720128923 is about 41474.4369823148. The cubic root of 1720128923 is about 1198.1752179839.

The spelling of 1720128923 in words is "one billion, seven hundred twenty million, one hundred twenty-eight thousand, nine hundred twenty-three".