1200420421 has 4 divisors (see below), whose sum is σ = 1200756832. Its totient is φ = 1200084012.

The previous prime is 1200420407. The next prime is 1200420433. The reversal of 1200420421 is 1240240021.

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 a de Polignac number, because none of the positive numbers 2^k-1200420421 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1200420395 and 1200420404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200426421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162795 + ... + 170008.

It is an arithmetic number, because the mean of its divisors is an integer number (300189208).

Almost surely, 2^1200420421 is an apocalyptic number.

It is an amenable number.

1200420421 is a deficient number, since it is larger than the sum of its proper divisors (336411).

1200420421 is an equidigital number, since it uses as much as digits as its factorization.

1200420421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336410.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 1200420421 is about 34647.0838744042. The cubic root of 1200420421 is about 1062.7826557975.

Adding to 1200420421 its reverse (1240240021), we get a palindrome (2440660442).

The spelling of 1200420421 in words is "one billion, two hundred million, four hundred twenty thousand, four hundred twenty-one".