21221406453453 has 16 divisors (see below), whose sum is σ = 29536336505856. Its totient is φ = 13539576997440.

The previous prime is 21221406453433. The next prime is 21221406453491. The reversal of 21221406453453 is 35435460412212.

It is not a de Polignac number, because 21221406453453 - 2¹⁶ = 21221406387917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221406453433) 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, 1567073901 + ... + 1567087442.

It is an arithmetic number, because the mean of its divisors is an integer number (1846021031616).

Almost surely, 2^{21221406453453} is an apocalyptic number.

It is an amenable number.

21221406453453 is a deficient number, since it is larger than the sum of its proper divisors (8314930052403).

21221406453453 is a wasteful number, since it uses less digits than its factorization.

21221406453453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3134161444.

The product of its (nonzero) digits is 691200, while the sum is 42.

Adding to 21221406453453 its reverse (35435460412212), we get a palindrome (56656866865665).

The spelling of 21221406453453 in words is "twenty-one trillion, two hundred twenty-one billion, four hundred six million, four hundred fifty-three thousand, four hundred fifty-three".