21152816280 has 640 divisors, whose sum is σ = 78428908800. Its totient is φ = 5094835200.

The previous prime is 21152816257. The next prime is 21152816281. The reversal of 21152816280 is 8261825112.

21152816280 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 28 + 1 + 628 + 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 not an unprimeable number, because it can be changed into a prime (21152816281) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 161471815 + ... + 161471945.

It is an arithmetic number, because the mean of its divisors is an integer number (122545170).

Almost surely, 2^21152816280 is an apocalyptic number.

21152816280 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 21152816280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39214454400).

21152816280 is an abundant number, since it is smaller than the sum of its proper divisors (57276092520).

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

21152816280 is a wasteful number, since it uses less digits than its factorization.

21152816280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The spelling of 21152816280 in words is "twenty-one billion, one hundred fifty-two million, eight hundred sixteen thousand, two hundred eighty".