23447921 has 18 divisors (see below), whose sum is σ = 28298790. Its totient is φ = 19371072.

The previous prime is 23447917. The next prime is 23447933. The reversal of 23447921 is 12974432.

It can be written as a sum of positive squares in 3 ways, for example, as 1254400 + 22193521 = 1120^2 + 4711^2 .

It is not a de Polignac number, because 23447921 - 2² = 23447917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23447621) 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 17 ways as a sum of consecutive naturals, for example, 40925 + ... + 41493.

It is an arithmetic number, because the mean of its divisors is an integer number (1572155).

Almost surely, 2^23447921 is an apocalyptic number.

It is an amenable number.

23447921 is a deficient number, since it is larger than the sum of its proper divisors (4850869).

23447921 is an equidigital number, since it uses as much as digits as its factorization.

23447921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641 (or 605 counting only the distinct ones).

The product of its digits is 12096, while the sum is 32.

The square root of 23447921 is about 4842.3053394019. The cubic root of 23447921 is about 286.2209688145.

The spelling of 23447921 in words is "twenty-three million, four hundred forty-seven thousand, nine hundred twenty-one".