1200000021 has 16 divisors (see below), whose sum is σ = 1792630848. Its totient is φ = 707616000.

The previous prime is 1199999993. The next prime is 1200000041.

It is a happy number.

1200000021 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1200000021 - 2¹¹ = 1199997973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1199999955 and 1200000009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200000041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 490180 + ... + 492621.

It is an arithmetic number, because the mean of its divisors is an integer number (112039428).

Almost surely, 2^1200000021 is an apocalyptic number.

1200000021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1200000021 is a deficient number, since it is larger than the sum of its proper divisors (592630827).

1200000021 is a wasteful number, since it uses less digits than its factorization.

1200000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 982852.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 1200000021 is about 34641.0164544864. The cubic root of 1200000021 is about 1062.6585753815.

It can be divided in two parts, 12000000 and 21, that added together give a palindrome (12000021).

The spelling of 1200000021 in words is "one billion, two hundred million, twenty-one", and thus it is an aban number.