21020047650 has 72 divisors (see below), whose sum is σ = 64541565504. Its totient is φ = 4804581600.

The previous prime is 21020047603. The next prime is 21020047667. The reversal of 21020047650 is 5674002012.

21020047650 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 0 + 0 + 4 + 7 + 650 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3333366 + ... + 3339665.

It is an arithmetic number, because the mean of its divisors is an integer number (896410632).

Almost surely, 2^21020047650 is an apocalyptic number.

21020047650 is an abundant number, since it is smaller than the sum of its proper divisors (43521517854).

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

21020047650 is a wasteful number, since it uses less digits than its factorization.

21020047650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6673056 (or 6673048 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

Adding to 21020047650 its reverse (5674002012), we get a palindrome (26694049662).

The spelling of 21020047650 in words is "twenty-one billion, twenty million, forty-seven thousand, six hundred fifty".