15621320220 has 144 divisors (see below), whose sum is σ = 48147208704. Its totient is φ = 3781500800.

The previous prime is 15621320207. The next prime is 15621320243. The reversal of 15621320220 is 2202312651.

15621320220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7484017 + ... + 7486103.

It is an arithmetic number, because the mean of its divisors is an integer number (334355616).

Almost surely, 2^15621320220 is an apocalyptic number.

15621320220 is a gapful number since it is divisible by the number (10) 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 15621320220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24073604352).

15621320220 is an abundant number, since it is smaller than the sum of its proper divisors (32525888484).

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

15621320220 is a wasteful number, since it uses less digits than its factorization.

15621320220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3152 (or 3139 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 15621320220 its reverse (2202312651), we get a palindrome (17823632871).

The spelling of 15621320220 in words is "fifteen billion, six hundred twenty-one million, three hundred twenty thousand, two hundred twenty".