21002022121 has 8 divisors (see below), whose sum is σ = 21126809088. Its totient is φ = 20877390000.

The previous prime is 21002022059. The next prime is 21002022133. The reversal of 21002022121 is 12122020012.

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 21002022121 - 2⁹ = 21002021609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002022421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 239251 + ... + 315031.

It is an arithmetic number, because the mean of its divisors is an integer number (2640851136).

Almost surely, 2^21002022121 is an apocalyptic number.

It is an amenable number.

21002022121 is a deficient number, since it is larger than the sum of its proper divisors (124786967).

21002022121 is a wasteful number, since it uses less digits than its factorization.

21002022121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77423.

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

Adding to 21002022121 its reverse (12122020012), we get a palindrome (33124042133).

The spelling of 21002022121 in words is "twenty-one billion, two million, twenty-two thousand, one hundred twenty-one".