20515531212544 has 72 divisors (see below), whose sum is σ = 41200369610400. Its totient is φ = 10195471257600.

The previous prime is 20515531212499. The next prime is 20515531212623. The reversal of 20515531212544 is 44521213551502.

It is a junction number, because it is equal to n+sod(n) for n = 20515531212497 and 20515531212506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27416814 + ... + 28155154.

It is an arithmetic number, because the mean of its divisors is an integer number (572227355700).

Almost surely, 2^{20515531212544} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20515531212544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20600184805200).

20515531212544 is an abundant number, since it is smaller than the sum of its proper divisors (20684838397856).

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

20515531212544 is an equidigital number, since it uses as much as digits as its factorization.

20515531212544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 739017 (or 739003 counting only the distinct ones).

The product of its (nonzero) digits is 240000, while the sum is 40.

The spelling of 20515531212544 in words is "twenty trillion, five hundred fifteen billion, five hundred thirty-one million, two hundred twelve thousand, five hundred forty-four".