1200021021 has 16 divisors (see below), whose sum is σ = 1855105920. Its totient is φ = 765230400.

The previous prime is 1200021013. The next prime is 1200021077. The reversal of 1200021021 is 1201200021.

It is not a de Polignac number, because 1200021021 - 2³ = 1200021013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1200020994 and 1200021012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200023021) 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, 965580 + ... + 966821.

It is an arithmetic number, because the mean of its divisors is an integer number (115944120).

Almost surely, 2^1200021021 is an apocalyptic number.

It is an amenable number.

1200021021 is a deficient number, since it is larger than the sum of its proper divisors (655084899).

1200021021 is a wasteful number, since it uses less digits than its factorization.

1200021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1932433 (or 1932427 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1200021021 is about 34641.3195620490. The cubic root of 1200021021 is about 1062.6647741869.

Adding to 1200021021 its reverse (1201200021), we get a palindrome (2401221042).

The spelling of 1200021021 in words is "one billion, two hundred million, twenty-one thousand, twenty-one".