21563930976 has 288 divisors, whose sum is σ = 71431712352. Its totient is φ = 5656412160.

The previous prime is 21563930957. The next prime is 21563931007. The reversal of 21563930976 is 67903936512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3275400 + ... + 3281976.

It is an arithmetic number, because the mean of its divisors is an integer number (248026779).

Almost surely, 2^21563930976 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21563930976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35715856176).

21563930976 is an abundant number, since it is smaller than the sum of its proper divisors (49867781376).

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

21563930976 is a wasteful number, since it uses less digits than its factorization.

21563930976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6662 (or 6647 counting only the distinct ones).

The product of its (nonzero) digits is 1837080, while the sum is 51.

The spelling of 21563930976 in words is "twenty-one billion, five hundred sixty-three million, nine hundred thirty thousand, nine hundred seventy-six".