21387563120 has 360 divisors, whose sum is σ = 64626144912. Its totient is φ = 6556999680.

The previous prime is 21387563111. The next prime is 21387563159. The reversal of 21387563120 is 2136578312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 31779104 + ... + 31779776.

Almost surely, 2^21387563120 is an apocalyptic number.

21387563120 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 21387563120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32313072456).

21387563120 is an abundant number, since it is smaller than the sum of its proper divisors (43238581792).

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

21387563120 is a wasteful number, since it uses less digits than its factorization.

21387563120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 21387563120 in words is "twenty-one billion, three hundred eighty-seven million, five hundred sixty-three thousand, one hundred twenty".