21363215513 has 4 divisors (see below), whose sum is σ = 21363834660. Its totient is φ = 21362596368.

The previous prime is 21363215501. The next prime is 21363215519. The reversal of 21363215513 is 31551236312.

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 12823977049 + 8539238464 = 113243^2 + 92408^2 .

It is a cyclic number.

It is not a de Polignac number, because 21363215513 - 2⁶ = 21363215449 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21363215513.

It is not an unprimeable number, because it can be changed into a prime (21363215519) 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, 254558 + ... + 327911.

It is an arithmetic number, because the mean of its divisors is an integer number (5340958665).

Almost surely, 2^21363215513 is an apocalyptic number.

It is an amenable number.

21363215513 is a deficient number, since it is larger than the sum of its proper divisors (619147).

21363215513 is an equidigital number, since it uses as much as digits as its factorization.

21363215513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619146.

The product of its digits is 16200, while the sum is 32.

The spelling of 21363215513 in words is "twenty-one billion, three hundred sixty-three million, two hundred fifteen thousand, five hundred thirteen".