21501543982464 has 2048 divisors, whose sum is σ = 83384598528000. Its totient is φ = 5300440104960.

The previous prime is 21501543982439. The next prime is 21501543982481. The reversal of 21501543982464 is 46428934510512.

21501543982464 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 1 + 5 + 4 + 398 + 246 + 4 = 666.

It is a super-2 number, since 2×21501543982464² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21501543982464.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 109144893214 + ... + 109144893410.

It is an arithmetic number, because the mean of its divisors is an integer number (40715136000).

Almost surely, 2^{21501543982464} is an apocalyptic number.

21501543982464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21501543982464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41692299264000).

21501543982464 is an abundant number, since it is smaller than the sum of its proper divisors (61883054545536).

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

21501543982464 is a wasteful number, since it uses less digits than its factorization.

21501543982464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533 (or 515 counting only the distinct ones).

The product of its (nonzero) digits is 8294400, while the sum is 54.

The spelling of 21501543982464 in words is "twenty-one trillion, five hundred one billion, five hundred forty-three million, nine hundred eighty-two thousand, four hundred sixty-four".