21505352400 has 180 divisors, whose sum is σ = 85291010272. Its totient is φ = 4915503360.

The previous prime is 21505352371. The next prime is 21505352459. The reversal of 21505352400 is 425350512.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (180).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 401494 + ... + 451893.

Almost surely, 2^21505352400 is an apocalyptic number.

21505352400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21505352400 is an abundant number, since it is smaller than the sum of its proper divisors (63785657872).

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

21505352400 is a wasteful number, since it uses less digits than its factorization.

21505352400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853418 (or 853404 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The spelling of 21505352400 in words is "twenty-one billion, five hundred five million, three hundred fifty-two thousand, four hundred".