13509206820 has 36 divisors (see below), whose sum is σ = 40977927900. Its totient is φ = 3602455104.

The previous prime is 13509206803. The next prime is 13509206881. The reversal of 13509206820 is 2860290531.

It can be written as a sum of positive squares in 2 ways, for example, as 1953816804 + 11555390016 = 44202^2 + 107496^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37525395 + ... + 37525754.

It is an arithmetic number, because the mean of its divisors is an integer number (1138275775).

Almost surely, 2^13509206820 is an apocalyptic number.

13509206820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13509206820 is an abundant number, since it is smaller than the sum of its proper divisors (27468721080).

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

13509206820 is a wasteful number, since it uses less digits than its factorization.

13509206820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75051164 (or 75051159 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 13509206820 in words is "thirteen billion, five hundred nine million, two hundred six thousand, eight hundred twenty".