221331212021 has 4 divisors (see below), whose sum is σ = 232980223200. Its totient is φ = 209682200844.

The previous prime is 221331212009. The next prime is 221331212083. The reversal of 221331212021 is 120212133122.

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 a de Polignac number, because none of the positive numbers 2^k-221331212021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221331211984 and 221331212002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221331212621) 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, 5824505561 + ... + 5824505598.

It is an arithmetic number, because the mean of its divisors is an integer number (58245055800).

Almost surely, 2^221331212021 is an apocalyptic number.

It is an amenable number.

221331212021 is a deficient number, since it is larger than the sum of its proper divisors (11649011179).

221331212021 is a wasteful number, since it uses less digits than its factorization.

221331212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11649011178.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 221331212021 its reverse (120212133122), we get a palindrome (341543345143).

The spelling of 221331212021 in words is "two hundred twenty-one billion, three hundred thirty-one million, two hundred twelve thousand, twenty-one".