21122021021 has 16 divisors (see below), whose sum is σ = 21991989888. Its totient is φ = 20269368000.

The previous prime is 21122021003. The next prime is 21122021029. The reversal of 21122021021 is 12012022112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122021021 is a prime.

It is a super-2 number, since 2×21122021021² (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 = 21122020987 and 21122021005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122021029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 972086 + ... + 993576.

It is an arithmetic number, because the mean of its divisors is an integer number (1374499368).

Almost surely, 2^21122021021 is an apocalyptic number.

It is an amenable number.

21122021021 is a deficient number, since it is larger than the sum of its proper divisors (869968867).

21122021021 is a wasteful number, since it uses less digits than its factorization.

21122021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21892.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21122021021 its reverse (12012022112), we get a palindrome (33134043133).

The spelling of 21122021021 in words is "twenty-one billion, one hundred twenty-two million, twenty-one thousand, twenty-one".