1224100021 has 4 divisors (see below), whose sum is σ = 1227008044. Its totient is φ = 1221192000.

The previous prime is 1224100001. The next prime is 1224100027. The reversal of 1224100021 is 1200014221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1200014221 = 7 ⋅171430603.

It can be written as a sum of positive squares in 2 ways, for example, as 637007121 + 587092900 = 25239^2 + 24230^2 .

It is a cyclic number.

It is not a de Polignac number, because 1224100021 - 2⁷ = 1224099893 is a prime.

It is a super-2 number, since 2×1224100021² = 2996841722824400882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1224099974 and 1224100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1224100027) 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, 1453380 + ... + 1454221.

It is an arithmetic number, because the mean of its divisors is an integer number (306752011).

Almost surely, 2^1224100021 is an apocalyptic number.

It is an amenable number.

1224100021 is a deficient number, since it is larger than the sum of its proper divisors (2908023).

1224100021 is an equidigital number, since it uses as much as digits as its factorization.

1224100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2908022.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 1224100021 is about 34987.1407948692. The cubic root of 1224100021 is about 1069.7253847332.

Adding to 1224100021 its reverse (1200014221), we get a palindrome (2424114242).

The spelling of 1224100021 in words is "one billion, two hundred twenty-four million, one hundred thousand, twenty-one".