21115334506520 has 96 divisors (see below), whose sum is σ = 50144236617600. Its totient is φ = 8001180988416.

The previous prime is 21115334506471. The next prime is 21115334506627. The reversal of 21115334506520 is 2560543351112.

It is a Harshad number since it is a multiple of its sum of digits (38).

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, 515906297 + ... + 515947223.

It is an arithmetic number, because the mean of its divisors is an integer number (522335798100).

Almost surely, 2^{21115334506520} is an apocalyptic number.

21115334506520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115334506520 is an abundant number, since it is smaller than the sum of its proper divisors (29028902111080).

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

21115334506520 is a wasteful number, since it uses less digits than its factorization.

21115334506520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76705 (or 76682 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 38.

Adding to 21115334506520 its reverse (2560543351112), we get a palindrome (23675877857632).

The spelling of 21115334506520 in words is "twenty-one trillion, one hundred fifteen billion, three hundred thirty-four million, five hundred six thousand, five hundred twenty".