1220242421 has 4 divisors (see below), whose sum is σ = 1233953100. Its totient is φ = 1206531744.

The previous prime is 1220242411. The next prime is 1220242469. The reversal of 1220242421 is 1242420221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1242420221 = 7 ⋅177488603.

It can be written as a sum of positive squares in 2 ways, for example, as 428945521 + 791296900 = 20711^2 + 28130^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220242421 - 2³⁰ = 146500597 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220242393 and 1220242402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220242411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6855206 + ... + 6855383.

It is an arithmetic number, because the mean of its divisors is an integer number (308488275).

Almost surely, 2^1220242421 is an apocalyptic number.

It is an amenable number.

1220242421 is a deficient number, since it is larger than the sum of its proper divisors (13710679).

1220242421 is an equidigital number, since it uses as much as digits as its factorization.

1220242421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13710678.

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 1220242421 is about 34931.9684672937. The cubic root of 1220242421 is about 1068.6004997911.

Adding to 1220242421 its reverse (1242420221), we get a palindrome (2462662642).

The spelling of 1220242421 in words is "one billion, two hundred twenty million, two hundred forty-two thousand, four hundred twenty-one".