21571501650 has 48 divisors (see below), whose sum is σ = 53513092800. Its totient is φ = 5750704960.

The previous prime is 21571501649. The next prime is 21571501669. The reversal of 21571501650 is 5610517512.

It is a happy number.

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, 538516 + ... + 577184.

It is an arithmetic number, because the mean of its divisors is an integer number (1114856100).

Almost surely, 2^21571501650 is an apocalyptic number.

21571501650 is an abundant number, since it is smaller than the sum of its proper divisors (31941591150).

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

21571501650 is a wasteful number, since it uses less digits than its factorization.

21571501650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42403 (or 42398 counting only the distinct ones).

The product of its (nonzero) digits is 10500, while the sum is 33.

The spelling of 21571501650 in words is "twenty-one billion, five hundred seventy-one million, five hundred one thousand, six hundred fifty".