21055540650 has 48 divisors (see below), whose sum is σ = 54966050400. Its totient is φ = 5319293760.

The previous prime is 21055540643. The next prime is 21055540651. The reversal of 21055540650 is 5604555012.

It is not an unprimeable number, because it can be changed into a prime (21055540651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3691105 + ... + 3696804.

It is an arithmetic number, because the mean of its divisors is an integer number (1145126050).

Almost surely, 2^21055540650 is an apocalyptic number.

21055540650 is an abundant number, since it is smaller than the sum of its proper divisors (33910509750).

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

21055540650 is a wasteful number, since it uses less digits than its factorization.

21055540650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7387943 (or 7387938 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 33.

The spelling of 21055540650 in words is "twenty-one billion, fifty-five million, five hundred forty thousand, six hundred fifty".