21022001021 has 12 divisors (see below), whose sum is σ = 24469361280. Its totient is φ = 18007660440.

The previous prime is 21022000903. The next prime is 21022001029. The reversal of 21022001021 is 12010022012.

It is a happy number.

It is not a de Polignac number, because 21022001021 - 2¹⁸ = 21021738877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21022000993 and 21022001011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022001029) 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 11 ways as a sum of consecutive naturals, for example, 53165 + ... + 211826.

It is an arithmetic number, because the mean of its divisors is an integer number (2039113440).

Almost surely, 2^21022001021 is an apocalyptic number.

It is an amenable number.

21022001021 is a deficient number, since it is larger than the sum of its proper divisors (3447360259).

21022001021 is a wasteful number, since it uses less digits than its factorization.

21022001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266624 (or 266617 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21022001021 its reverse (12010022012), we get a palindrome (33032023033).

The spelling of 21022001021 in words is "twenty-one billion, twenty-two million, one thousand, twenty-one".