21455404441 has 4 divisors (see below), whose sum is σ = 21455699472. Its totient is φ = 21455109412.

The previous prime is 21455404423. The next prime is 21455404463. The reversal of 21455404441 is 14440455412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21455404441 - 2¹⁷ = 21455273369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21455404397 and 21455404406.

It is not an unprimeable number, because it can be changed into a prime (21455404471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47550 + ... + 212536.

It is an arithmetic number, because the mean of its divisors is an integer number (5363924868).

Almost surely, 2^21455404441 is an apocalyptic number.

It is an amenable number.

21455404441 is a deficient number, since it is larger than the sum of its proper divisors (295031).

21455404441 is a wasteful number, since it uses less digits than its factorization.

21455404441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295030.

The product of its (nonzero) digits is 51200, while the sum is 34.

Adding to 21455404441 its reverse (14440455412), we get a palindrome (35895859853).

The spelling of 21455404441 in words is "twenty-one billion, four hundred fifty-five million, four hundred four thousand, four hundred forty-one".