13621709 has 4 divisors (see below), whose sum is σ = 14423004. Its totient is φ = 12820416.

The previous prime is 13621697. The next prime is 13621723. The reversal of 13621709 is 90712631.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90712631 = 19 ⋅4774349.

It can be written as a sum of positive squares in 2 ways, for example, as 12096484 + 1525225 = 3478^2 + 1235^2 .

It is a cyclic number.

It is not a de Polignac number, because 13621709 - 2⁴ = 13621693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13621789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400622 + ... + 400655.

It is an arithmetic number, because the mean of its divisors is an integer number (3605751).

Almost surely, 2^13621709 is an apocalyptic number.

It is an amenable number.

13621709 is a deficient number, since it is larger than the sum of its proper divisors (801295).

13621709 is an equidigital number, since it uses as much as digits as its factorization.

13621709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 801294.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 13621709 is about 3690.7599488452. The cubic root of 13621709 is about 238.8235773703.

The spelling of 13621709 in words is "thirteen million, six hundred twenty-one thousand, seven hundred nine".