20515221770436 has 144 divisors (see below), whose sum is σ = 54264373572864. Its totient is φ = 6522750229248.

The previous prime is 20515221770377. The next prime is 20515221770437. The reversal of 20515221770436 is 63407712251502.

20515221770436 is a `hidden beast` number, since 2 + 0 + 5 + 1 + 522 + 17 + 70 + 43 + 6 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 20515221770391 and 20515221770400.

It is not an unprimeable number, because it can be changed into a prime (20515221770437) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1582103625 + ... + 1582116591.

Almost surely, 2^{20515221770436} 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 20515221770436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27132186786432).

20515221770436 is an abundant number, since it is smaller than the sum of its proper divisors (33749151802428).

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

20515221770436 is a wasteful number, since it uses less digits than its factorization.

20515221770436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18210 (or 18205 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 45.

The spelling of 20515221770436 in words is "twenty trillion, five hundred fifteen billion, two hundred twenty-one million, seven hundred seventy thousand, four hundred thirty-six".