23403521 has 2 divisors, whose sum is σ = 23403522. Its totient is φ = 23403520.

The previous prime is 23403511. The next prime is 23403533. The reversal of 23403521 is 12530432.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22193521 + 1210000 = 4711^2 + 1100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23403521 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 23403493 and 23403502.

It is not a weakly prime, because it can be changed into another prime (23403511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11701760 + 11701761.

It is an arithmetic number, because the mean of its divisors is an integer number (11701761).

Almost surely, 2^23403521 is an apocalyptic number.

It is an amenable number.

23403521 is a deficient number, since it is larger than the sum of its proper divisors (1).

23403521 is an equidigital number, since it uses as much as digits as its factorization.

23403521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 23403521 is about 4837.7185738734. The cubic root of 23403521 is about 286.0401959902.

Adding to 23403521 its reverse (12530432), we get a palindrome (35933953).

The spelling of 23403521 in words is "twenty-three million, four hundred three thousand, five hundred twenty-one".