13720405 has 4 divisors (see below), whose sum is σ = 16464492. Its totient is φ = 10976320.

The previous prime is 13720403. The next prime is 13720409. The reversal of 13720405 is 50402731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50402731 = 337 ⋅149563.

It can be written as a sum of positive squares in 2 ways, for example, as 6543364 + 7177041 = 2558^2 + 2679^2 .

It is not a de Polignac number, because 13720405 - 2¹ = 13720403 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13720403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1372036 + ... + 1372045.

It is an arithmetic number, because the mean of its divisors is an integer number (4116123).

Almost surely, 2^13720405 is an apocalyptic number.

It is an amenable number.

13720405 is a deficient number, since it is larger than the sum of its proper divisors (2744087).

13720405 is an equidigital number, since it uses as much as digits as its factorization.

13720405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2744086.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 13720405 is about 3704.1065049483. The cubic root of 13720405 is about 239.3989880907.

The spelling of 13720405 in words is "thirteen million, seven hundred twenty thousand, four hundred five".