21021110222021 has 48 divisors (see below), whose sum is σ = 27885467571696. Its totient is φ = 15652458952704.

The previous prime is 21021110221997. The next prime is 21021110222039. The reversal of 21021110222021 is 12022201112012.

It can be written as a sum of positive squares in 8 ways, for example, as 1437874384996 + 19583235837025 = 1199114^2 + 4425295^2 .

It is not a de Polignac number, because 21021110222021 - 2²⁶ = 21021043113157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021110222041) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 145870415 + ... + 146014451.

It is an arithmetic number, because the mean of its divisors is an integer number (580947241077).

Almost surely, 2^{21021110222021} is an apocalyptic number.

It is an amenable number.

21021110222021 is a deficient number, since it is larger than the sum of its proper divisors (6864357349675).

21021110222021 is a wasteful number, since it uses less digits than its factorization.

21021110222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157558 (or 157551 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21021110222021 its reverse (12022201112012), we get a palindrome (33043311334033).

The spelling of 21021110222021 in words is "twenty-one trillion, twenty-one billion, one hundred ten million, two hundred twenty-two thousand, twenty-one".