21039395850 has 144 divisors (see below), whose sum is σ = 62276576544. Its totient is φ = 5049840000.

The previous prime is 21039395831. The next prime is 21039395873. The reversal of 21039395850 is 5859393012.

21039395850 is a `hidden beast` number, since 2 + 1 + 0 + 39 + 39 + 585 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 21039395796 and 21039395805.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 478909 + ... + 520991.

It is an arithmetic number, because the mean of its divisors is an integer number (432476226).

Almost surely, 2^21039395850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21039395850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31138288272).

21039395850 is an abundant number, since it is smaller than the sum of its proper divisors (41237180694).

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

21039395850 is a wasteful number, since it uses less digits than its factorization.

21039395850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42213 (or 42205 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The spelling of 21039395850 in words is "twenty-one billion, thirty-nine million, three hundred ninety-five thousand, eight hundred fifty".