21033534400 has 84 divisors (see below), whose sum is σ = 51869250592. Its totient is φ = 8394946560.

The previous prime is 21033534371. The next prime is 21033534419. The reversal of 21033534400 is 443533012.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 726604 + ... + 754996.

Almost surely, 2^21033534400 is an apocalyptic number.

21033534400 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 21033534400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25934625296).

21033534400 is an abundant number, since it is smaller than the sum of its proper divisors (30835716192).

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

21033534400 is a wasteful number, since it uses less digits than its factorization.

21033534400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28878 (or 28863 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 25.

The spelling of 21033534400 in words is "twenty-one billion, thirty-three million, five hundred thirty-four thousand, four hundred".