21250616513 has 4 divisors (see below), whose sum is σ = 24286418880. Its totient is φ = 18214814148.

The previous prime is 21250616473. The next prime is 21250616521. The reversal of 21250616513 is 31561605212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21250616513 - 2³⁰ = 20176874689 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 21250616513.

It is not an unprimeable number, because it can be changed into a prime (21250616533) 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, 1517901173 + ... + 1517901186.

It is an arithmetic number, because the mean of its divisors is an integer number (6071604720).

Almost surely, 2^21250616513 is an apocalyptic number.

It is an amenable number.

21250616513 is a deficient number, since it is larger than the sum of its proper divisors (3035802367).

21250616513 is an equidigital number, since it uses as much as digits as its factorization.

21250616513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3035802366.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21250616513 in words is "twenty-one billion, two hundred fifty million, six hundred sixteen thousand, five hundred thirteen".