21530678400 has 1728 divisors, whose sum is σ = 104031064800. Its totient is φ = 4180377600.

The previous prime is 21530678387. The next prime is 21530678447. The reversal of 21530678400 is 487603512.

21530678400 is a `hidden beast` number, since 21 + 530 + 67 + 8 + 40 + 0 = 666.

It is a super-2 number, since 2×21530678400² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 294940764 + ... + 294940836.

Almost surely, 2^21530678400 is an apocalyptic number.

21530678400 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 21530678400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52015532400).

21530678400 is an abundant number, since it is smaller than the sum of its proper divisors (82500386400).

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

21530678400 is a wasteful number, since it uses less digits than its factorization.

21530678400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 21530678400 in words is "twenty-one billion, five hundred thirty million, six hundred seventy-eight thousand, four hundred".