21351433600 has 192 divisors, whose sum is σ = 62902045440. Its totient is φ = 7002040320.

The previous prime is 21351433589. The next prime is 21351433603. The reversal of 21351433600 is 633415312.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351433603) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 494479 + ... + 535921.

It is an arithmetic number, because the mean of its divisors is an integer number (327614820).

Almost surely, 2^21351433600 is an apocalyptic number.

21351433600 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 21351433600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31451022720).

21351433600 is an abundant number, since it is smaller than the sum of its proper divisors (41550611840).

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

21351433600 is a wasteful number, since it uses less digits than its factorization.

21351433600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41497 (or 41480 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 28.

Adding to 21351433600 its reverse (633415312), we get a palindrome (21984848912).

The spelling of 21351433600 in words is "twenty-one billion, three hundred fifty-one million, four hundred thirty-three thousand, six hundred".