1221443454541 has 16 divisors (see below), whose sum is σ = 1311097590000. Its totient is φ = 1133769719808.

The previous prime is 1221443454523. The next prime is 1221443454559. The reversal of 1221443454541 is 1454543441221.

It is an interprime number because it is at equal distance from previous prime (1221443454523) and next prime (1221443454559).

It can be written as a sum of positive squares in 8 ways, for example, as 309458564100 + 911984890441 = 556290^2 + 954979^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221443454541 - 2¹⁷ = 1221443323469 is a prime.

It is a super-2 number, since 2×1221443454541² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221443454494 and 1221443454503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221443458541) 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, 27961485 + ... + 28005133.

It is an arithmetic number, because the mean of its divisors is an integer number (81943599375).

Almost surely, 2^{1221443454541} is an apocalyptic number.

It is an amenable number.

1221443454541 is a deficient number, since it is larger than the sum of its proper divisors (89654135459).

1221443454541 is a wasteful number, since it uses less digits than its factorization.

1221443454541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66288.

The product of its digits is 307200, while the sum is 40.

Adding to 1221443454541 its reverse (1454543441221), we get a palindrome (2675986895762).

The spelling of 1221443454541 in words is "one trillion, two hundred twenty-one billion, four hundred forty-three million, four hundred fifty-four thousand, five hundred forty-one".