2122220021 has 4 divisors (see below), whose sum is σ = 2123093292. Its totient is φ = 2121346752.

The previous prime is 2122220003. The next prime is 2122220047. The reversal of 2122220021 is 1200222212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2059888996 + 62331025 = 45386^2 + 7895^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2122220021 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 = 2122219978 and 2122220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2182220021) 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, 432980 + ... + 437853.

It is an arithmetic number, because the mean of its divisors is an integer number (530773323).

Almost surely, 2^2122220021 is an apocalyptic number.

It is an amenable number.

2122220021 is a deficient number, since it is larger than the sum of its proper divisors (873271).

2122220021 is an equidigital number, since it uses as much as digits as its factorization.

2122220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 873270.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 2122220021 is about 46067.5593123838. The cubic root of 2122220021 is about 1285.0799146856.

Adding to 2122220021 its reverse (1200222212), we get a palindrome (3322442233).

The spelling of 2122220021 in words is "two billion, one hundred twenty-two million, two hundred twenty thousand, twenty-one".