23666821 has 2 divisors, whose sum is σ = 23666822. Its totient is φ = 23666820.

The previous prime is 23666807. The next prime is 23666849. The reversal of 23666821 is 12866632.

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., 14333796 + 9333025 = 3786^2 + 3055^2 .

It is a cyclic number.

It is not a de Polignac number, because 23666821 - 2⁷ = 23666693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23666801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11833410 + 11833411.

It is an arithmetic number, because the mean of its divisors is an integer number (11833411).

Almost surely, 2^23666821 is an apocalyptic number.

It is an amenable number.

23666821 is a deficient number, since it is larger than the sum of its proper divisors (1).

23666821 is an equidigital number, since it uses as much as digits as its factorization.

23666821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 34.

The square root of 23666821 is about 4864.8557018682. The cubic root of 23666821 is about 287.1088912478.

The spelling of 23666821 in words is "twenty-three million, six hundred sixty-six thousand, eight hundred twenty-one".