21515113405040 has 120 divisors (see below), whose sum is σ = 51199344102192. Its totient is φ = 8408147374080.

The previous prime is 21515113405007. The next prime is 21515113405069. The reversal of 21515113405040 is 4050431151512.

It is a junction number, because it is equal to n+sod(n) for n = 21515113404988 and 21515113405006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100800512 + ... + 101013728.

Almost surely, 2^{21515113405040} is an apocalyptic number.

21515113405040 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 21515113405040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25599672051096).

21515113405040 is an abundant number, since it is smaller than the sum of its proper divisors (29684230697152).

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

21515113405040 is a wasteful number, since it uses less digits than its factorization.

21515113405040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213895 (or 213842 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 32.

Adding to 21515113405040 its reverse (4050431151512), we get a palindrome (25565544556552).

The spelling of 21515113405040 in words is "twenty-one trillion, five hundred fifteen billion, one hundred thirteen million, four hundred five thousand, forty".