1021440121 has 16 divisors (see below), whose sum is σ = 1165803408. Its totient is φ = 886579200.

The previous prime is 1021440113. The next prime is 1021440149. The reversal of 1021440121 is 1210441201.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 318096 + 1021122025 = 564^2 + 31955^2 .

It is not a de Polignac number, because 1021440121 - 2³ = 1021440113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021440095 and 1021440104.

It is not an unprimeable number, because it can be changed into a prime (1021440521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 458791 + ... + 461011.

It is an arithmetic number, because the mean of its divisors is an integer number (72862713).

Almost surely, 2^1021440121 is an apocalyptic number.

It is an amenable number.

1021440121 is a deficient number, since it is larger than the sum of its proper divisors (144363287).

1021440121 is a wasteful number, since it uses less digits than its factorization.

1021440121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4332.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 1021440121 is about 31959.9768616938. The cubic root of 1021440121 is about 1007.0962313863.

Adding to 1021440121 its reverse (1210441201), we get a palindrome (2231881322).

The spelling of 1021440121 in words is "one billion, twenty-one million, four hundred forty thousand, one hundred twenty-one".