1021645563120 has 1280 divisors, whose sum is σ = 4440982425600. Its totient is φ = 210153553920.

The previous prime is 1021645563091. The next prime is 1021645563137. The reversal of 1021645563120 is 213655461201.

1021645563120 is a `hidden beast` number, since 1 + 0 + 2 + 1 + 645 + 5 + 6 + 3 + 1 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 1666631934 + ... + 1666632546.

It is an arithmetic number, because the mean of its divisors is an integer number (3469517520).

Almost surely, 2^{1021645563120} is an apocalyptic number.

1021645563120 is a gapful number since it is divisible by the number (10) 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 1021645563120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2220491212800).

1021645563120 is an abundant number, since it is smaller than the sum of its proper divisors (3419336862480).

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

1021645563120 is a wasteful number, since it uses less digits than its factorization.

1021645563120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855 (or 843 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 1021645563120 in words is "one trillion, twenty-one billion, six hundred forty-five million, five hundred sixty-three thousand, one hundred twenty".