1221724 has 12 divisors (see below), whose sum is σ = 2443504. Its totient is φ = 523584.

The previous prime is 1221707. The next prime is 1221749. The reversal of 1221724 is 4271221.

It is a happy number.

1221724 is an admirable number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21789 + ... + 21844.

2^1221724 is an apocalyptic number.

1221724 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1221724 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221724 is a wasteful number, since it uses less digits than its factorization.

1221724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43644 (or 43642 counting only the distinct ones).

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

The square root of 1221724 is about 1105.3162443391. The cubic root of 1221724 is about 106.9032811628.

Adding to 1221724 its reverse (4271221), we get a palindrome (5492945).

It can be divided in two parts, 12 and 21724, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 1221724 in words is "one million, two hundred twenty-one thousand, seven hundred twenty-four".