23781921 has 4 divisors (see below), whose sum is σ = 31709232. Its totient is φ = 15854612.

The previous prime is 23781913. The next prime is 23781937. The reversal of 23781921 is 12918732.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 23781921 - 2³ = 23781913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (23781971) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3963651 + ... + 3963656.

It is an arithmetic number, because the mean of its divisors is an integer number (7927308).

Almost surely, 2^23781921 is an apocalyptic number.

It is an amenable number.

23781921 is a deficient number, since it is larger than the sum of its proper divisors (7927311).

23781921 is an equidigital number, since it uses as much as digits as its factorization.

23781921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7927310.

The product of its digits is 6048, while the sum is 33.

The square root of 23781921 is about 4876.6710981980. The cubic root of 23781921 is about 287.5735756242.

The spelling of 23781921 in words is "twenty-three million, seven hundred eighty-one thousand, nine hundred twenty-one".