1721918 has 32 divisors (see below), whose sum is σ = 3048192. Its totient is φ = 721600.

The previous prime is 1721911. The next prime is 1721921. The reversal of 1721918 is 8191271.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20705 + ... + 20787.

It is an arithmetic number, because the mean of its divisors is an integer number (95256).

2^1721918 is an apocalyptic number.

1721918 is a deficient number, since it is larger than the sum of its proper divisors (1326274).

1721918 is a wasteful number, since it uses less digits than its factorization.

1721918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160.

The product of its digits is 1008, while the sum is 29.

The square root of 1721918 is about 1312.2187317669. The cubic root of 1721918 is about 119.8590474643.

The spelling of 1721918 in words is "one million, seven hundred twenty-one thousand, nine hundred eighteen".