207928409 has 4 divisors (see below), whose sum is σ = 223922916. Its totient is φ = 191933904.

The previous prime is 207928387. The next prime is 207928417. The reversal of 207928409 is 904829702.

207928409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 121066009 + 86862400 = 11003^2 + 9320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-207928409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (207928459) 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, 7997234 + ... + 7997259.

It is an arithmetic number, because the mean of its divisors is an integer number (55980729).

Almost surely, 2^207928409 is an apocalyptic number.

It is an amenable number.

207928409 is a deficient number, since it is larger than the sum of its proper divisors (15994507).

207928409 is a wasteful number, since it uses less digits than its factorization.

207928409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15994506.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 207928409 is about 14419.7229168941. The cubic root of 207928409 is about 592.4312289400.

The spelling of 207928409 in words is "two hundred seven million, nine hundred twenty-eight thousand, four hundred nine".