1720121 has 8 divisors (see below), whose sum is σ = 1862784. Its totient is φ = 1578960.

The previous prime is 1720109. The next prime is 1720123. The reversal of 1720121 is 1210271.

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 1720121 - 2⁶ = 1720057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1720096 and 1720105.

It is not an unprimeable number, because it can be changed into a prime (1720123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3776 + ... + 4206.

It is an arithmetic number, because the mean of its divisors is an integer number (232848).

2^1720121 is an apocalyptic number.

It is an amenable number.

1720121 is a deficient number, since it is larger than the sum of its proper divisors (142663).

1720121 is a wasteful number, since it uses less digits than its factorization.

1720121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 1720121 is about 1311.5338348666. The cubic root of 1720121 is about 119.8173378363.

Adding to 1720121 its reverse (1210271), we get a palindrome (2930392).

The spelling of 1720121 in words is "one million, seven hundred twenty thousand, one hundred twenty-one".