21122002021 has 12 divisors (see below), whose sum is σ = 21664643616. Its totient is φ = 20592646880.

The previous prime is 21122001991. The next prime is 21122002049. The reversal of 21122002021 is 12020022112.

It is a happy number.

It is not a de Polignac number, because 21122002021 - 2¹³ = 21121993829 is a prime.

It is a super-2 number, since 2×21122002021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122001992 and 21122002010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122002721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3101406 + ... + 3108208.

It is an arithmetic number, because the mean of its divisors is an integer number (1805386968).

Almost surely, 2^21122002021 is an apocalyptic number.

It is an amenable number.

21122002021 is a deficient number, since it is larger than the sum of its proper divisors (542641595).

21122002021 is an equidigital number, since it uses as much as digits as its factorization.

21122002021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8732 (or 8691 counting only the distinct ones).

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

Adding to 21122002021 its reverse (12020022112), we get a palindrome (33142024133).

The spelling of 21122002021 in words is "twenty-one billion, one hundred twenty-two million, two thousand, twenty-one".