20521001220 has 48 divisors (see below), whose sum is σ = 58432691520. Its totient is φ = 5379515776.

The previous prime is 20521001177. The next prime is 20521001231. The reversal of 20521001220 is 2210012502.

It is a super-2 number, since 2×20521001220² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20521001220.

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 15 ways as a sum of consecutive naturals, for example, 2894907 + ... + 2901986.

It is an arithmetic number, because the mean of its divisors is an integer number (1217347740).

Almost surely, 2^20521001220 is an apocalyptic number.

20521001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20521001220 is an abundant number, since it is smaller than the sum of its proper divisors (37911690300).

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

20521001220 is a wasteful number, since it uses less digits than its factorization.

20521001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5796964 (or 5796962 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

Adding to 20521001220 its reverse (2210012502), we get a palindrome (22731013722).

The spelling of 20521001220 in words is "twenty billion, five hundred twenty-one million, one thousand, two hundred twenty".