21101212222021 has 8 divisors (see below), whose sum is σ = 21122176529664. Its totient is φ = 21080248497840.

The previous prime is 21101212222009. The next prime is 21101212222043. The reversal of 21101212222021 is 12022221210112.

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 21101212222021 - 2⁵ = 21101212221989 is a prime.

It is a super-2 number, since 2×21101212222021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21101212222021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101212222621) 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, 126405216 + ... + 126572038.

It is an arithmetic number, because the mean of its divisors is an integer number (2640272066208).

Almost surely, 2^{21101212222021} is an apocalyptic number.

It is an amenable number.

21101212222021 is a deficient number, since it is larger than the sum of its proper divisors (20964307643).

21101212222021 is a wasteful number, since it uses less digits than its factorization.

21101212222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291731.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21101212222021 its reverse (12022221210112), we get a palindrome (33123433432133).

The spelling of 21101212222021 in words is "twenty-one trillion, one hundred one billion, two hundred twelve million, two hundred twenty-two thousand, twenty-one".