211221121220021 has 16 divisors (see below), whose sum is σ = 231712316098560. Its totient is φ = 190944823947120.

The previous prime is 211221121220003. The next prime is 211221121220047. The reversal of 211221121220021 is 120022121122112.

It is a cyclic number.

It is not a de Polignac number, because 211221121220021 - 2²² = 211221117025717 is a prime.

It is a super-2 number, since 2×211221121220021² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211221121219975 and 211221121220002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221121220071) 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, 267829346 + ... + 268616828.

It is an arithmetic number, because the mean of its divisors is an integer number (14482019756160).

Almost surely, 2^{211221121220021} is an apocalyptic number.

It is an amenable number.

211221121220021 is a deficient number, since it is larger than the sum of its proper divisors (20491194878539).

211221121220021 is a wasteful number, since it uses less digits than its factorization.

211221121220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 923896.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 211221121220021 its reverse (120022121122112), we get a palindrome (331243242342133).

The spelling of 211221121220021 in words is "two hundred eleven trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".