21005974752 has 96 divisors (see below), whose sum is σ = 63514386432. Its totient is φ = 5954425344.

The previous prime is 21005974733. The next prime is 21005974831. The reversal of 21005974752 is 25747950012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-3 number, since 3×21005974752³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37723 + ... + 208410.

It is an arithmetic number, because the mean of its divisors is an integer number (661608192).

Almost surely, 2^21005974752 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 21005974752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31757193216).

21005974752 is an abundant number, since it is smaller than the sum of its proper divisors (42508411680).

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

21005974752 is a wasteful number, since it uses less digits than its factorization.

21005974752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246280 (or 246272 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 42.

The spelling of 21005974752 in words is "twenty-one billion, five million, nine hundred seventy-four thousand, seven hundred fifty-two".