2121220001 has 4 divisors (see below), whose sum is σ = 2126008752. Its totient is φ = 2116431252.

The previous prime is 2121219977. The next prime is 2121220081. The reversal of 2121220001 is 1000221212.

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 2121220001 - 2⁶ = 2121219937 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 (2121220081) 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, 2393711 + ... + 2394596.

It is an arithmetic number, because the mean of its divisors is an integer number (531502188).

Almost surely, 2^2121220001 is an apocalyptic number.

It is an amenable number.

2121220001 is a deficient number, since it is larger than the sum of its proper divisors (4788751).

2121220001 is an equidigital number, since it uses as much as digits as its factorization.

2121220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4788750.

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

The square root of 2121220001 is about 46056.7041916809. The cubic root of 2121220001 is about 1284.8780337135.

Adding to 2121220001 its reverse (1000221212), we get a palindrome (3121441213).

The spelling of 2121220001 in words is "two billion, one hundred twenty-one million, two hundred twenty thousand, one".