21252210640145 has 8 divisors (see below), whose sum is σ = 25578328297704. Its totient is φ = 16951318159104.

The previous prime is 21252210640117. The next prime is 21252210640153. The reversal of 21252210640145 is 54104601225212.

It is a Cunningham number, because it is equal to 4610012²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 1 + 21252210640144 = 1^2 + 4610012^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21252210640145 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, 6306292274 + ... + 6306295643.

It is an arithmetic number, because the mean of its divisors is an integer number (3197291037213).

Almost surely, 2^{21252210640145} is an apocalyptic number.

It is an amenable number.

21252210640145 is a deficient number, since it is larger than the sum of its proper divisors (4326117657559).

21252210640145 is a wasteful number, since it uses less digits than its factorization.

21252210640145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12612588259.

The product of its (nonzero) digits is 38400, while the sum is 35.

Adding to 21252210640145 its reverse (54104601225212), we get a palindrome (75356811865357).

The spelling of 21252210640145 in words is "twenty-one trillion, two hundred fifty-two billion, two hundred ten million, six hundred forty thousand, one hundred forty-five".