21544530433 has 4 divisors (see below), whose sum is σ = 21599915220. Its totient is φ = 21489145648.

The previous prime is 21544530409. The next prime is 21544530437. The reversal of 21544530433 is 33403544512.

It is a happy number.

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 2403254529 + 19141275904 = 49023^2 + 138352^2 .

It is a cyclic number.

It is not a de Polignac number, because 21544530433 - 2⁵ = 21544530401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21544530437) 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, 27691810 + ... + 27692587.

It is an arithmetic number, because the mean of its divisors is an integer number (5399978805).

Almost surely, 2^21544530433 is an apocalyptic number.

It is an amenable number.

21544530433 is a deficient number, since it is larger than the sum of its proper divisors (55384787).

21544530433 is an equidigital number, since it uses as much as digits as its factorization.

21544530433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55384786.

The product of its (nonzero) digits is 86400, while the sum is 34.

The spelling of 21544530433 in words is "twenty-one billion, five hundred forty-four million, five hundred thirty thousand, four hundred thirty-three".