20438423135550 has 960 divisors, whose sum is σ = 69593535728640. Its totient is φ = 4346706862080.

The previous prime is 20438423135521. The next prime is 20438423135551. The reversal of 20438423135550 is 5553132483402.

20438423135550 is a `hidden beast` number, since 2 + 0 + 4 + 3 + 84 + 2 + 3 + 13 + 5 + 550 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20438423135496 and 20438423135505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20438423135551) by changing a digit.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 3731679412 + ... + 3731684888.

It is an arithmetic number, because the mean of its divisors is an integer number (72493266384).

Almost surely, 2^{20438423135550} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20438423135550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34796767864320).

20438423135550 is an abundant number, since it is smaller than the sum of its proper divisors (49155112593090).

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

20438423135550 is a wasteful number, since it uses less digits than its factorization.

20438423135550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5687 (or 5673 counting only the distinct ones).

The product of its (nonzero) digits is 1728000, while the sum is 45.

The spelling of 20438423135550 in words is "twenty trillion, four hundred thirty-eight billion, four hundred twenty-three million, one hundred thirty-five thousand, five hundred fifty".