23121505 has 32 divisors (see below), whose sum is σ = 31850496. Its totient is φ = 15960000.

The previous prime is 23121491. The next prime is 23121517. The reversal of 23121505 is 50512132.

It is not a de Polignac number, because 23121505 - 2⁵ = 23121473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 120960 + ... + 121150.

It is an arithmetic number, because the mean of its divisors is an integer number (995328).

Almost surely, 2^23121505 is an apocalyptic number.

It is an amenable number.

23121505 is a deficient number, since it is larger than the sum of its proper divisors (8728991).

23121505 is a wasteful number, since it uses less digits than its factorization.

23121505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 23121505 is about 4808.4826088903. The cubic root of 23121505 is about 284.8866071937.

Adding to 23121505 its reverse (50512132), we get a palindrome (73633637).

It can be divided in two parts, 231 and 21505, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 23121505 in words is "twenty-three million, one hundred twenty-one thousand, five hundred five".