21099657600 has 960 divisors, whose sum is σ = 92283602400. Its totient is φ = 4644864000.

The previous prime is 21099657599. The next prime is 21099657611. The reversal of 21099657600 is 675699012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 52617400 + ... + 52617800.

Almost surely, 2^21099657600 is an apocalyptic number.

21099657600 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 21099657600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46141801200).

21099657600 is an abundant number, since it is smaller than the sum of its proper divisors (71183944800).

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

21099657600 is a wasteful number, since it uses less digits than its factorization.

21099657600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473 (or 447 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

The spelling of 21099657600 in words is "twenty-one billion, ninety-nine million, six hundred fifty-seven thousand, six hundred".