21010423440 has 160 divisors (see below), whose sum is σ = 70924924800. Its totient is φ = 5124833280.

The previous prime is 21010423417. The next prime is 21010423451. The reversal of 21010423440 is 4432401012.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52800 + ... + 211680.

It is an arithmetic number, because the mean of its divisors is an integer number (443280780).

Almost surely, 2^21010423440 is an apocalyptic number.

21010423440 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 21010423440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35462462400).

21010423440 is an abundant number, since it is smaller than the sum of its proper divisors (49914501360).

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

21010423440 is a wasteful number, since it uses less digits than its factorization.

21010423440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158945 (or 158939 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21010423440 its reverse (4432401012), we get a palindrome (25442824452).

The spelling of 21010423440 in words is "twenty-one billion, ten million, four hundred twenty-three thousand, four hundred forty".