21017645609040 has 960 divisors, whose sum is σ = 77676528384000. Its totient is φ = 5073990045696.

The previous prime is 21017645609011. The next prime is 21017645609089. The reversal of 21017645609040 is 4090654671012.

21017645609040 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 76 + 456 + 0 + 90 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 15023334261 + ... + 15023335659.

It is an arithmetic number, because the mean of its divisors is an integer number (80913050400).

Almost surely, 2^{21017645609040} is an apocalyptic number.

21017645609040 is a gapful number since it is divisible by the number (20) 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 21017645609040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38838264192000).

21017645609040 is an abundant number, since it is smaller than the sum of its proper divisors (56658882774960).

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

21017645609040 is a wasteful number, since it uses less digits than its factorization.

21017645609040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1984 (or 1975 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21017645609040 in words is "twenty-one trillion, seventeen billion, six hundred forty-five million, six hundred nine thousand, forty".