21264280380 has 240 divisors, whose sum is σ = 76606311936. Its totient is φ = 4836827520.

The previous prime is 21264280319. The next prime is 21264280417. The reversal of 21264280380 is 8308246212.

21264280380 is a `hidden beast` number, since 2 + 1 + 2 + 642 + 8 + 0 + 3 + 8 + 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 79 ways as a sum of consecutive naturals, for example, 2388297 + ... + 2397183.

Almost surely, 2^21264280380 is an apocalyptic number.

21264280380 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 21264280380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38303155968).

21264280380 is an abundant number, since it is smaller than the sum of its proper divisors (55342031556).

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

21264280380 is a wasteful number, since it uses less digits than its factorization.

21264280380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9126 (or 9115 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The spelling of 21264280380 in words is "twenty-one billion, two hundred sixty-four million, two hundred eighty thousand, three hundred eighty".