21021020221111 has 16 divisors (see below), whose sum is σ = 21625901892000. Its totient is φ = 20420626705920.

The previous prime is 21021020221081. The next prime is 21021020221121. The reversal of 21021020221111 is 11112202012012.

It is a cyclic number.

It is not a de Polignac number, because 21021020221111 - 2¹¹ = 21021020219063 is a prime.

It is a super-4 number, since 4×21021020221111⁴ (a number of 54 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021020221121) 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, 16406755 + ... + 17641531.

It is an arithmetic number, because the mean of its divisors is an integer number (1351618868250).

Almost surely, 2^{21021020221111} is an apocalyptic number.

21021020221111 is a deficient number, since it is larger than the sum of its proper divisors (604881670889).

21021020221111 is a wasteful number, since it uses less digits than its factorization.

21021020221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236594.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21021020221111 its reverse (11112202012012), we get a palindrome (32133222233123).

The spelling of 21021020221111 in words is "twenty-one trillion, twenty-one billion, twenty million, two hundred twenty-one thousand, one hundred eleven".