21104459640 has 384 divisors, whose sum is σ = 76286059200. Its totient is φ = 5017436160.

The previous prime is 21104459591. The next prime is 21104459659. The reversal of 21104459640 is 4695440112.

21104459640 is a `hidden beast` number, since 2 + 1 + 1 + 0 + 4 + 4 + 5 + 9 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21104459595 and 21104459604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 82118392 + ... + 82118648.

Almost surely, 2^21104459640 is an apocalyptic number.

21104459640 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 21104459640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38143029600).

21104459640 is an abundant number, since it is smaller than the sum of its proper divisors (55181599560).

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

21104459640 is a wasteful number, since it uses less digits than its factorization.

21104459640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607 (or 600 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

Adding to 21104459640 its reverse (4695440112), we get a palindrome (25799899752).

The spelling of 21104459640 in words is "twenty-one billion, one hundred four million, four hundred fifty-nine thousand, six hundred forty".