12640520 has 64 divisors (see below), whose sum is σ = 31201200. Its totient is φ = 4587520.

The previous prime is 12640517. The next prime is 12640531. The reversal of 12640520 is 2504621.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10125124 + 2515396 = 3182^2 + 1586^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 12640492 and 12640501.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19400 + ... + 20040.

Almost surely, 2^12640520 is an apocalyptic number.

12640520 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 12640520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15600600).

12640520 is an abundant number, since it is smaller than the sum of its proper divisors (18560680).

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

12640520 is a wasteful number, since it uses less digits than its factorization.

12640520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698 (or 694 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 12640520 is about 3555.3508968877. The cubic root of 12640520 is about 232.9458512199.

It can be divided in two parts, 126405 and 20, that multiplied together give a square (2528100 = 1590²).

The spelling of 12640520 in words is "twelve million, six hundred forty thousand, five hundred twenty".