21513501002053 has 4 divisors (see below), whose sum is σ = 21513673935468. Its totient is φ = 21513328068640.

The previous prime is 21513501002047. The next prime is 21513501002087. The reversal of 21513501002053 is 35020010531512.

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 12744600121764 + 8768900880289 = 3569958^2 + 2961233^2 .

It is a cyclic number.

It is not a de Polignac number, because 21513501002053 - 2⁹ = 21513501001541 is a prime.

It is a super-2 number, since 2×21513501002053² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513501002003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86279968 + ... + 86528953.

It is an arithmetic number, because the mean of its divisors is an integer number (5378418483867).

Almost surely, 2^{21513501002053} is an apocalyptic number.

It is an amenable number.

21513501002053 is a deficient number, since it is larger than the sum of its proper divisors (172933415).

21513501002053 is a wasteful number, since it uses less digits than its factorization.

21513501002053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172933414.

The product of its (nonzero) digits is 4500, while the sum is 28.

Adding to 21513501002053 its reverse (35020010531512), we get a palindrome (56533511533565).

The spelling of 21513501002053 in words is "twenty-one trillion, five hundred thirteen billion, five hundred one million, two thousand, fifty-three".