21500515532420 has 12 divisors (see below), whose sum is σ = 45151082618124. Its totient is φ = 8600206212960.

The previous prime is 21500515532399. The next prime is 21500515532429. The reversal of 21500515532420 is 2423551500512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16832902195264 + 4667613337156 = 4102792^2 + 2160466^2 .

It is not an unprimeable number, because it can be changed into a prime (21500515532429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 537512888291 + ... + 537512888330.

It is an arithmetic number, because the mean of its divisors is an integer number (3762590218177).

Almost surely, 2^{21500515532420} is an apocalyptic number.

21500515532420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21500515532420 is an abundant number, since it is smaller than the sum of its proper divisors (23650567085704).

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

21500515532420 is a wasteful number, since it uses less digits than its factorization.

21500515532420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075025776630 (or 1075025776628 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 35.

The spelling of 21500515532420 in words is "twenty-one trillion, five hundred billion, five hundred fifteen million, five hundred thirty-two thousand, four hundred twenty".