21020120221 has 8 divisors (see below), whose sum is σ = 21093493824. Its totient is φ = 20946784320.

The previous prime is 21020120213. The next prime is 21020120227. The reversal of 21020120221 is 12202102012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020120221 - 2³ = 21020120213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020120227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1544181 + ... + 1557733.

It is an arithmetic number, because the mean of its divisors is an integer number (2636686728).

Almost surely, 2^21020120221 is an apocalyptic number.

It is an amenable number.

21020120221 is a deficient number, since it is larger than the sum of its proper divisors (73373603).

21020120221 is a wasteful number, since it uses less digits than its factorization.

21020120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18851.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21020120221 its reverse (12202102012), we get a palindrome (33222222233).

The spelling of 21020120221 in words is "twenty-one billion, twenty million, one hundred twenty thousand, two hundred twenty-one".