1721224 has 8 divisors (see below), whose sum is σ = 3227310. Its totient is φ = 860608.

The previous prime is 1721201. The next prime is 1721227. The reversal of 1721224 is 4221271.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 964324 + 756900 = 982^2 + 870^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×1721224² = 5925224116352, which contains 22 as substring.

It is a hoax number, since the sum of its digits (19) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1721227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107569 + ... + 107584.

2^1721224 is an apocalyptic number.

It is an amenable number.

1721224 is a deficient number, since it is larger than the sum of its proper divisors (1506086).

1721224 is a wasteful number, since it uses less digits than its factorization.

1721224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215159 (or 215155 counting only the distinct ones).

The product of its digits is 224, while the sum is 19.

The square root of 1721224 is about 1311.9542674956. The cubic root of 1721224 is about 119.8429426795.

Adding to 1721224 its reverse (4221271), we get a palindrome (5942495).

The spelling of 1721224 in words is "one million, seven hundred twenty-one thousand, two hundred twenty-four".