21501976650 has 576 divisors, whose sum is σ = 73085607936. Its totient is φ = 4124736000.

The previous prime is 21501976637. The next prime is 21501976651. The reversal of 21501976650 is 5667910512.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21501976651) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 57645864 + ... + 57646236.

It is an arithmetic number, because the mean of its divisors is an integer number (126884736).

Almost surely, 2^21501976650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21501976650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36542803968).

21501976650 is an abundant number, since it is smaller than the sum of its proper divisors (51583631286).

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

21501976650 is a wasteful number, since it uses less digits than its factorization.

21501976650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467 (or 455 counting only the distinct ones).

The product of its (nonzero) digits is 113400, while the sum is 42.

The spelling of 21501976650 in words is "twenty-one billion, five hundred one million, nine hundred seventy-six thousand, six hundred fifty".