21221533520153 has 4 divisors (see below), whose sum is σ = 21221551732788. Its totient is φ = 21221515307520.

The previous prime is 21221533520147. The next prime is 21221533520171. The reversal of 21221533520153 is 35102533512212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6313224087769 + 14908309432384 = 2512613^2 + 3861128^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221533520153 - 2¹⁴ = 21221533503769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221533520183) 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, 7229576 + ... + 9731897.

It is an arithmetic number, because the mean of its divisors is an integer number (5305387933197).

Almost surely, 2^{21221533520153} is an apocalyptic number.

It is an amenable number.

21221533520153 is a deficient number, since it is larger than the sum of its proper divisors (18212635).

21221533520153 is a wasteful number, since it uses less digits than its factorization.

21221533520153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18212634.

The product of its (nonzero) digits is 54000, while the sum is 35.

The spelling of 21221533520153 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred thirty-three million, five hundred twenty thousand, one hundred fifty-three".