15720109 has 4 divisors (see below), whose sum is σ = 16403616. Its totient is φ = 15036604.

The previous prime is 15720101. The next prime is 15720167. The reversal of 15720109 is 90102751.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90102751 = 3917 ⋅23003.

It is a cyclic number.

It is not a de Polignac number, because 15720109 - 2³ = 15720101 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 (15720101) 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, 341719 + ... + 341764.

It is an arithmetic number, because the mean of its divisors is an integer number (4100904).

Almost surely, 2^15720109 is an apocalyptic number.

It is an amenable number.

15720109 is a deficient number, since it is larger than the sum of its proper divisors (683507).

15720109 is an equidigital number, since it uses as much as digits as its factorization.

15720109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 683506.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 15720109 is about 3964.8592661026. The cubic root of 15720109 is about 250.5062222642.

The spelling of 15720109 in words is "fifteen million, seven hundred twenty thousand, one hundred nine".