1728696121 has 8 divisors (see below), whose sum is σ = 1787065088. Its totient is φ = 1670490000.

The previous prime is 1728696097. The next prime is 1728696131. The reversal of 1728696121 is 1216968271.

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

It is a cyclic number.

It is not a de Polignac number, because 1728696121 - 2¹⁹ = 1728171833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1728696131) 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 7 ways as a sum of consecutive naturals, for example, 18930 + ... + 61771.

It is an arithmetic number, because the mean of its divisors is an integer number (223383136).

Almost surely, 2^1728696121 is an apocalyptic number.

It is an amenable number.

1728696121 is a deficient number, since it is larger than the sum of its proper divisors (58368967).

1728696121 is an equidigital number, since it uses as much as digits as its factorization.

1728696121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81423.

The product of its digits is 72576, while the sum is 43.

The square root of 1728696121 is about 41577.5915728653. The cubic root of 1728696121 is about 1200.1611174870.

The spelling of 1728696121 in words is "one billion, seven hundred twenty-eight million, six hundred ninety-six thousand, one hundred twenty-one".