1021200121 has 4 divisors (see below), whose sum is σ = 1026040144. Its totient is φ = 1016360100.

The previous prime is 1021200119. The next prime is 1021200197. The reversal of 1021200121 is 1210021201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1021200121 - 2¹ = 1021200119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021200098 and 1021200107.

It is not an unprimeable number, because it can be changed into a prime (1021200101) 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, 2419695 + ... + 2420116.

It is an arithmetic number, because the mean of its divisors is an integer number (256510036).

Almost surely, 2^1021200121 is an apocalyptic number.

It is an amenable number.

1021200121 is a deficient number, since it is larger than the sum of its proper divisors (4840023).

1021200121 is an equidigital number, since it uses as much as digits as its factorization.

1021200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4840022.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1021200121 is about 31956.2219450297. The cubic root of 1021200121 is about 1007.0173486326.

Adding to 1021200121 its reverse (1210021201), we get a palindrome (2231221322).

The spelling of 1021200121 in words is "one billion, twenty-one million, two hundred thousand, one hundred twenty-one".