21040032320 has 336 divisors, whose sum is σ = 56593313280. Its totient is φ = 7436697600.

The previous prime is 21040032313. The next prime is 21040032331. The reversal of 21040032320 is 2323004012.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

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, 117541991 + ... + 117542169.

It is an arithmetic number, because the mean of its divisors is an integer number (168432480).

Almost surely, 2^21040032320 is an apocalyptic number.

21040032320 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 21040032320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28296656640).

21040032320 is an abundant number, since it is smaller than the sum of its proper divisors (35553280960).

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

21040032320 is a wasteful number, since it uses less digits than its factorization.

21040032320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 275 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

Adding to 21040032320 its reverse (2323004012), we get a palindrome (23363036332).

The spelling of 21040032320 in words is "twenty-one billion, forty million, thirty-two thousand, three hundred twenty".