21004240040 has 192 divisors, whose sum is σ = 56085099840. Its totient is φ = 7057290240.

The previous prime is 21004239979. The next prime is 21004240069. The reversal of 21004240040 is 4004240012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 40314980 + ... + 40315500.

It is an arithmetic number, because the mean of its divisors is an integer number (292109895).

Almost surely, 2^21004240040 is an apocalyptic number.

21004240040 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 21004240040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28042549920).

21004240040 is an abundant number, since it is smaller than the sum of its proper divisors (35080859800).

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

21004240040 is a wasteful number, since it uses less digits than its factorization.

21004240040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920 (or 909 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

Adding to 21004240040 its reverse (4004240012), we get a palindrome (25008480052).

The spelling of 21004240040 in words is "twenty-one billion, four million, two hundred forty thousand, forty".