2221020421 has 4 divisors (see below), whose sum is σ = 2224766412. Its totient is φ = 2217274432.

The previous prime is 2221020407. The next prime is 2221020427. The reversal of 2221020421 is 1240201222.

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 1928439396 + 292581025 = 43914^2 + 17105^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221020421 - 2¹³ = 2221012229 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2221020395 and 2221020404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2221020427) 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, 1872106 + ... + 1873291.

It is an arithmetic number, because the mean of its divisors is an integer number (556191603).

Almost surely, 2^2221020421 is an apocalyptic number.

It is an amenable number.

2221020421 is a deficient number, since it is larger than the sum of its proper divisors (3745991).

2221020421 is an equidigital number, since it uses as much as digits as its factorization.

2221020421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3745990.

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

The square root of 2221020421 is about 47127.7033282973. The cubic root of 2221020421 is about 1304.7205933335.

Adding to 2221020421 its reverse (1240201222), we get a palindrome (3461221643).

The spelling of 2221020421 in words is "two billion, two hundred twenty-one million, twenty thousand, four hundred twenty-one".