20205221520 has 160 divisors (see below), whose sum is σ = 68408193024. Its totient is φ = 4892659200.

The previous prime is 20205221513. The next prime is 20205221527. The reversal of 20205221520 is 2512250202.

It is an interprime number because it is at equal distance from previous prime (20205221513) and next prime (20205221527).

It is a super-2 number, since 2×20205221520² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20205221527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2612379 + ... + 2620101.

Almost surely, 2^20205221520 is an apocalyptic number.

20205221520 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 20205221520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34204096512).

20205221520 is an abundant number, since it is smaller than the sum of its proper divisors (48202971504).

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

20205221520 is a wasteful number, since it uses less digits than its factorization.

20205221520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8741 (or 8735 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

Adding to 20205221520 its reverse (2512250202), we get a palindrome (22717471722).

The spelling of 20205221520 in words is "twenty billion, two hundred five million, two hundred twenty-one thousand, five hundred twenty".