15521320020 has 96 divisors (see below), whose sum is σ = 45792028800. Its totient is φ = 3917320704.

The previous prime is 15521320019. The next prime is 15521320037. The reversal of 15521320020 is 2002312551.

It is a super-2 number, since 2×15521320020² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1258122 + ... + 1270398.

It is an arithmetic number, because the mean of its divisors is an integer number (477000300).

Almost surely, 2^15521320020 is an apocalyptic number.

15521320020 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 15521320020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22896014400).

15521320020 is an abundant number, since it is smaller than the sum of its proper divisors (30270708780).

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

15521320020 is a wasteful number, since it uses less digits than its factorization.

15521320020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13417 (or 13415 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

Adding to 15521320020 its reverse (2002312551), we get a palindrome (17523632571).

The spelling of 15521320020 in words is "fifteen billion, five hundred twenty-one million, three hundred twenty thousand, twenty".