222121210021 has 4 divisors (see below), whose sum is σ = 222122444544. Its totient is φ = 222119975500.

The previous prime is 222121210009. The next prime is 222121210033. The reversal of 222121210021 is 120012121222.

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 an interprime number because it is at equal distance from previous prime (222121210009) and next prime (222121210033).

It is a cyclic number.

It is not a de Polignac number, because 222121210021 - 2⁹ = 222121209509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 222121209977 and 222121210004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (222121210081) 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, 289285 + ... + 726586.

It is an arithmetic number, because the mean of its divisors is an integer number (55530611136).

Almost surely, 2^222121210021 is an apocalyptic number.

It is an amenable number.

222121210021 is a deficient number, since it is larger than the sum of its proper divisors (1234523).

222121210021 is a wasteful number, since it uses less digits than its factorization.

222121210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1234522.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 222121210021 its reverse (120012121222), we get a palindrome (342133331243).

The spelling of 222121210021 in words is "two hundred twenty-two billion, one hundred twenty-one million, two hundred ten thousand, twenty-one".