21013254505 has 8 divisors (see below), whose sum is σ = 25242370632. Its totient is φ = 16792960128.

The previous prime is 21013254419. The next prime is 21013254529. The reversal of 21013254505 is 50545231012.

It can be written as a sum of positive squares in 4 ways, for example, as 6310236969 + 14703017536 = 79437^2 + 121256^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21013254505 - 2⁷ = 21013254377 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2200194 + ... + 2209723.

It is an arithmetic number, because the mean of its divisors is an integer number (3155296329).

Almost surely, 2^21013254505 is an apocalyptic number.

It is an amenable number.

21013254505 is a deficient number, since it is larger than the sum of its proper divisors (4229116127).

21013254505 is an equidigital number, since it uses as much as digits as its factorization.

21013254505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4410875.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21013254505 its reverse (50545231012), we get a palindrome (71558485517).

The spelling of 21013254505 in words is "twenty-one billion, thirteen million, two hundred fifty-four thousand, five hundred five".