1221020033 has 4 divisors (see below), whose sum is σ = 1260407808. Its totient is φ = 1181632260.

The previous prime is 1221019979. The next prime is 1221020069. The reversal of 1221020033 is 3300201221.

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 not a de Polignac number, because 1221020033 - 2²⁴ = 1204242817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1221020093) 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, 19693841 + ... + 19693902.

It is an arithmetic number, because the mean of its divisors is an integer number (315101952).

Almost surely, 2^1221020033 is an apocalyptic number.

It is an amenable number.

1221020033 is a deficient number, since it is larger than the sum of its proper divisors (39387775).

1221020033 is an equidigital number, since it uses as much as digits as its factorization.

1221020033 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39387774.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 1221020033 is about 34943.0970722402. The cubic root of 1221020033 is about 1068.8274438005.

Adding to 1221020033 its reverse (3300201221), we get a palindrome (4521221254).

The spelling of 1221020033 in words is "one billion, two hundred twenty-one million, twenty thousand, thirty-three".