21065404850 has 48 divisors (see below), whose sum is σ = 44855754048. Its totient is φ = 7210050240.

The previous prime is 21065404819. The next prime is 21065404907. The reversal of 21065404850 is 5840456012.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21065404850.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 154184 + ... + 256716.

It is an arithmetic number, because the mean of its divisors is an integer number (934494876).

Almost surely, 2^21065404850 is an apocalyptic number.

21065404850 is an abundant number, since it is smaller than the sum of its proper divisors (23790349198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21065404850 is a wasteful number, since it uses less digits than its factorization.

21065404850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103139 (or 103134 counting only the distinct ones).

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

The spelling of 21065404850 in words is "twenty-one billion, sixty-five million, four hundred four thousand, eight hundred fifty".