21022012021 has 8 divisors (see below), whose sum is σ = 21170426400. Its totient is φ = 20873695632.

The previous prime is 21022012013. The next prime is 21022012057. The reversal of 21022012021 is 12021022012.

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 21022012021 - 2³ = 21022012013 is a prime.

It is a super-2 number, since 2×21022012021² (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 = 21022011992 and 21022012010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022012421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 436486 + ... + 482248.

It is an arithmetic number, because the mean of its divisors is an integer number (2646303300).

Almost surely, 2^21022012021 is an apocalyptic number.

It is an amenable number.

21022012021 is a deficient number, since it is larger than the sum of its proper divisors (148414379).

21022012021 is a wasteful number, since it uses less digits than its factorization.

21022012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48995.

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

Adding to 21022012021 its reverse (12021022012), we get a palindrome (33043034033).

Subtracting from 21022012021 its reverse (12021022012), we obtain a palindrome (9000990009).

The spelling of 21022012021 in words is "twenty-one billion, twenty-two million, twelve thousand, twenty-one".