21024342111221 has 8 divisors (see below), whose sum is σ = 21537311206488. Its totient is φ = 20511381600000.

The previous prime is 21024342111211. The next prime is 21024342111233. The reversal of 21024342111221 is 12211124342012.

It can be written as a sum of positive squares in 4 ways, for example, as 676529280196 + 20347812831025 = 822514^2 + 4510855^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-21024342111221 is a prime.

It is a super-2 number, since 2×21024342111221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024342111211) 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, 2958551 + ... + 7127531.

It is an arithmetic number, because the mean of its divisors is an integer number (2692163900811).

Almost surely, 2^{21024342111221} is an apocalyptic number.

It is an amenable number.

21024342111221 is a deficient number, since it is larger than the sum of its proper divisors (512969095267).

21024342111221 is a wasteful number, since it uses less digits than its factorization.

21024342111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4292023.

The product of its (nonzero) digits is 1536, while the sum is 26.

Adding to 21024342111221 its reverse (12211124342012), we get a palindrome (33235466453233).

The spelling of 21024342111221 in words is "twenty-one trillion, twenty-four billion, three hundred forty-two million, one hundred eleven thousand, two hundred twenty-one".