21215252546650 has 24 divisors (see below), whose sum is σ = 39468942915264. Its totient is φ = 8484257324400.

The previous prime is 21215252546639. The next prime is 21215252546699. The reversal of 21215252546650 is 5664525251212.

It is a self number, because there is not a number n which added to its sum of digits gives 21215252546650.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45859906 + ... + 46320205.

It is an arithmetic number, because the mean of its divisors is an integer number (1644539288136).

Almost surely, 2^{21215252546650} is an apocalyptic number.

21215252546650 is a deficient number, since it is larger than the sum of its proper divisors (18253690368614).

21215252546650 is a wasteful number, since it uses less digits than its factorization.

21215252546650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92184726 (or 92184721 counting only the distinct ones).

The product of its (nonzero) digits is 1440000, while the sum is 46.

Adding to 21215252546650 its reverse (5664525251212), we get a palindrome (26879777797862).

The spelling of 21215252546650 in words is "twenty-one trillion, two hundred fifteen billion, two hundred fifty-two million, five hundred forty-six thousand, six hundred fifty".