21221123021 has 8 divisors (see below), whose sum is σ = 24254717760. Its totient is φ = 18188029728.

The previous prime is 21221122987. The next prime is 21221123041. The reversal of 21221123021 is 12032112212.

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 21221123021 - 2⁶ = 21221122957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221123041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29816 + ... + 208161.

It is an arithmetic number, because the mean of its divisors is an integer number (3031839720).

Almost surely, 2^21221123021 is an apocalyptic number.

It is an amenable number.

21221123021 is a deficient number, since it is larger than the sum of its proper divisors (3033594739).

21221123021 is a wasteful number, since it uses less digits than its factorization.

21221123021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250723.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21221123021 its reverse (12032112212), we get a palindrome (33253235233).

The spelling of 21221123021 in words is "twenty-one billion, two hundred twenty-one million, one hundred twenty-three thousand, twenty-one".