21361240320 has 432 divisors, whose sum is σ = 80178009408. Its totient is φ = 4832378880.

The previous prime is 21361240283. The next prime is 21361240399. The reversal of 21361240320 is 2304216312.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20132590 + ... + 20133650.

It is an arithmetic number, because the mean of its divisors is an integer number (185597244).

Almost surely, 2^21361240320 is an apocalyptic number.

21361240320 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 21361240320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40089004704).

21361240320 is an abundant number, since it is smaller than the sum of its proper divisors (58816769088).

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

21361240320 is a wasteful number, since it uses less digits than its factorization.

21361240320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206 (or 1185 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

Adding to 21361240320 its reverse (2304216312), we get a palindrome (23665456632).

The spelling of 21361240320 in words is "twenty-one billion, three hundred sixty-one million, two hundred forty thousand, three hundred twenty".