21040121760 has 576 divisors, whose sum is σ = 80771644800. Its totient is φ = 4584480768.

The previous prime is 21040121759. The next prime is 21040121771. The reversal of 21040121760 is 6712104012.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21040121760.

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, 74346579 + ... + 74346861.

It is an arithmetic number, because the mean of its divisors is an integer number (140228550).

Almost surely, 2^21040121760 is an apocalyptic number.

21040121760 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 21040121760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40385822400).

21040121760 is an abundant number, since it is smaller than the sum of its proper divisors (59731523040).

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

21040121760 is a wasteful number, since it uses less digits than its factorization.

21040121760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

Adding to 21040121760 its reverse (6712104012), we get a palindrome (27752225772).

The spelling of 21040121760 in words is "twenty-one billion, forty million, one hundred twenty-one thousand, seven hundred sixty".