1200221021 has 4 divisors (see below), whose sum is σ = 1201872672. Its totient is φ = 1198569372.

The previous prime is 1200220951. The next prime is 1200221023. The reversal of 1200221021 is 1201220021.

It is a happy number.

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-1200221021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1200220993 and 1200221011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200221023) 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, 824735 + ... + 826188.

It is an arithmetic number, because the mean of its divisors is an integer number (300468168).

Almost surely, 2^1200221021 is an apocalyptic number.

It is an amenable number.

1200221021 is a deficient number, since it is larger than the sum of its proper divisors (1651651).

1200221021 is an equidigital number, since it uses as much as digits as its factorization.

1200221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1651650.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1200221021 is about 34644.2061678428. The cubic root of 1200221021 is about 1062.7238068052.

Adding to 1200221021 its reverse (1201220021), we get a palindrome (2401441042).

The spelling of 1200221021 in words is "one billion, two hundred million, two hundred twenty-one thousand, twenty-one".