21545442211321 has 64 divisors (see below), whose sum is σ = 26102360678400. Its totient is φ = 17395992117504.

The previous prime is 21545442211301. The next prime is 21545442211331. The reversal of 21545442211321 is 12311224454512.

It is not a de Polignac number, because 21545442211321 - 2²¹ = 21545440114169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21545442211301) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 681219910 + ... + 681251536.

It is an arithmetic number, because the mean of its divisors is an integer number (407849385600).

Almost surely, 2^{21545442211321} is an apocalyptic number.

It is an amenable number.

21545442211321 is a deficient number, since it is larger than the sum of its proper divisors (4556918467079).

21545442211321 is a wasteful number, since it uses less digits than its factorization.

21545442211321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32246.

The product of its digits is 76800, while the sum is 37.

Adding to 21545442211321 its reverse (12311224454512), we get a palindrome (33856666665833).

The spelling of 21545442211321 in words is "twenty-one trillion, five hundred forty-five billion, four hundred forty-two million, two hundred eleven thousand, three hundred twenty-one".