20505240000 has 840 divisors, whose sum is σ = 85824527360. Its totient is φ = 4582656000.

The previous prime is 20505239969. The next prime is 20505240029. The reversal of 20505240000 is 4250502.

It is a tau number, because it is divible by the number of its divisors (840).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 199079949 + ... + 199080051.

Almost surely, 2^20505240000 is an apocalyptic number.

20505240000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20505240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42912263680).

20505240000 is an abundant number, since it is smaller than the sum of its proper divisors (65319287360).

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

20505240000 is a wasteful number, since it uses less digits than its factorization.

20505240000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 18.

Adding to 20505240000 its reverse (4250502), we get a palindrome (20509490502).

The spelling of 20505240000 in words is "twenty billion, five hundred five million, two hundred forty thousand".