1720979 has 4 divisors (see below), whose sum is σ = 1853376. Its totient is φ = 1588584.

The previous prime is 1720973. The next prime is 1720991. The reversal of 1720979 is 9790271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9790271 = 109 ⋅89819.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1720979 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720973) 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, 66179 + ... + 66204.

It is an arithmetic number, because the mean of its divisors is an integer number (463344).

2^1720979 is an apocalyptic number.

1720979 is a deficient number, since it is larger than the sum of its proper divisors (132397).

1720979 is a wasteful number, since it uses less digits than its factorization.

1720979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132396.

The product of its (nonzero) digits is 7938, while the sum is 35.

The square root of 1720979 is about 1311.8608920156. The cubic root of 1720979 is about 119.8372562389.

The spelling of 1720979 in words is "one million, seven hundred twenty thousand, nine hundred seventy-nine".