1200030021 has 6 divisors (see below), whose sum is σ = 1733376710. Its totient is φ = 800020008.

The previous prime is 1200029993. The next prime is 1200030049. The reversal of 1200030021 is 1200300021.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1200029993) and next prime (1200030049).

It can be written as a sum of positive squares in only one way, i.e., 1008761121 + 191268900 = 31761^2 + 13830^2 .

It is not a de Polignac number, because 1200030021 - 2⁷ = 1200029893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 133336669 = 1200030021 / (1 + 2 + 0 + 0 + 0 + 3 + 0 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1200029985 and 1200030012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200030071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 66668326 + ... + 66668343.

Almost surely, 2^1200030021 is an apocalyptic number.

It is an amenable number.

1200030021 is a deficient number, since it is larger than the sum of its proper divisors (533346689).

1200030021 is a wasteful number, since it uses less digits than its factorization.

1200030021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133336675 (or 133336672 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 1200030021 is about 34641.4494644782. The cubic root of 1200030021 is about 1062.6674307956.

Adding to 1200030021 its reverse (1200300021), we get a palindrome (2400330042).

The spelling of 1200030021 in words is "one billion, two hundred million, thirty thousand, twenty-one".