12400720 has 20 divisors (see below), whose sum is σ = 28831860. Its totient is φ = 4960256.

The previous prime is 12400699. The next prime is 12400721. The reversal of 12400720 is 2700421.

It can be written as a sum of positive squares in 2 ways, for example, as 6906384 + 5494336 = 2628^2 + 2344^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 12400694 and 12400703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12400721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77425 + ... + 77584.

It is an arithmetic number, because the mean of its divisors is an integer number (1441593).

Almost surely, 2^12400720 is an apocalyptic number.

12400720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12400720 is an abundant number, since it is smaller than the sum of its proper divisors (16431140).

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

12400720 is a wasteful number, since it uses less digits than its factorization.

12400720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155022 (or 155016 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 12400720 is about 3521.4656039780. The cubic root of 12400720 is about 231.4633852157.

The spelling of 12400720 in words is "twelve million, four hundred thousand, seven hundred twenty".