23919821 has 2 divisors, whose sum is σ = 23919822. Its totient is φ = 23919820.

The previous prime is 23919787. The next prime is 23919859. The reversal of 23919821 is 12891932.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20160100 + 3759721 = 4490^2 + 1939^2 .

It is a cyclic number.

It is not a de Polignac number, because 23919821 - 2¹⁸ = 23657677 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23916821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11959910 + 11959911.

It is an arithmetic number, because the mean of its divisors is an integer number (11959911).

Almost surely, 2^23919821 is an apocalyptic number.

It is an amenable number.

23919821 is a deficient number, since it is larger than the sum of its proper divisors (1).

23919821 is an equidigital number, since it uses as much as digits as its factorization.

23919821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 23919821 is about 4890.7894045849. The cubic root of 23919821 is about 288.1283386667.

The spelling of 23919821 in words is "twenty-three million, nine hundred nineteen thousand, eight hundred twenty-one".