23209991 has 8 divisors (see below), whose sum is σ = 26557824. Its totient is φ = 19870200.

The previous prime is 23209973. The next prime is 23209993. The reversal of 23209991 is 19990232.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-23209991 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 (23209993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6716 + ... + 9566.

It is an arithmetic number, because the mean of its divisors is an integer number (3319728).

Almost surely, 2^23209991 is an apocalyptic number.

23209991 is a deficient number, since it is larger than the sum of its proper divisors (3347833).

23209991 is a wasteful number, since it uses less digits than its factorization.

23209991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4021.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 23209991 is about 4817.6748541179. The cubic root of 23209991 is about 285.2495649237.

The spelling of 23209991 in words is "twenty-three million, two hundred nine thousand, nine hundred ninety-one".