20420255520 has 960 divisors, whose sum is σ = 87254931456. Its totient is φ = 4399349760.

The previous prime is 20420255519. The next prime is 20420255521. The reversal of 20420255520 is 2555202402.

It is an interprime number because it is at equal distance from previous prime (20420255519) and next prime (20420255521).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20420255521) by changing a digit.

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 159 ways as a sum of consecutive naturals, for example, 149052892 + ... + 149053028.

Almost surely, 2^20420255520 is an apocalyptic number.

20420255520 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 20420255520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43627465728).

20420255520 is an abundant number, since it is smaller than the sum of its proper divisors (66834675936).

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

20420255520 is a wasteful number, since it uses less digits than its factorization.

20420255520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 27.

Adding to 20420255520 its reverse (2555202402), we get a palindrome (22975457922).

The spelling of 20420255520 in words is "twenty billion, four hundred twenty million, two hundred fifty-five thousand, five hundred twenty".