21573548753 has 4 divisors (see below), whose sum is σ = 21576788388. Its totient is φ = 21570309120.

The previous prime is 21573548749. The next prime is 21573548779. The reversal of 21573548753 is 35784537512.

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 1359249424 + 20214299329 = 36868^2 + 142177^2 .

It is a cyclic number.

It is not a de Polignac number, because 21573548753 - 2² = 21573548749 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21573548053) 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, 1609808 + ... + 1623153.

It is an arithmetic number, because the mean of its divisors is an integer number (5394197097).

Almost surely, 2^21573548753 is an apocalyptic number.

It is an amenable number.

21573548753 is a deficient number, since it is larger than the sum of its proper divisors (3239635).

21573548753 is an equidigital number, since it uses as much as digits as its factorization.

21573548753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3239634.

The product of its digits is 3528000, while the sum is 50.

The spelling of 21573548753 in words is "twenty-one billion, five hundred seventy-three million, five hundred forty-eight thousand, seven hundred fifty-three".