21329581745 has 8 divisors (see below), whose sum is σ = 25596344040. Its totient is φ = 17063101440.

The previous prime is 21329581739. The next prime is 21329581747. The reversal of 21329581745 is 54718592312.

It can be written as a sum of positive squares in 4 ways, for example, as 1058656369 + 20270925376 = 32537^2 + 142376^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21329581745 - 2⁴ = 21329581729 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21329581745.

It is not an unprimeable number, because it can be changed into a prime (21329581747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171335 + ... + 268355.

It is an arithmetic number, because the mean of its divisors is an integer number (3199543005).

Almost surely, 2^21329581745 is an apocalyptic number.

It is an amenable number.

21329581745 is a deficient number, since it is larger than the sum of its proper divisors (4266762295).

21329581745 is an equidigital number, since it uses as much as digits as its factorization.

21329581745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140995.

The product of its digits is 604800, while the sum is 47.

The spelling of 21329581745 in words is "twenty-one billion, three hundred twenty-nine million, five hundred eighty-one thousand, seven hundred forty-five".