23821989 has 4 divisors (see below), whose sum is σ = 31762656. Its totient is φ = 15881324.

The previous prime is 23821979. The next prime is 23822003. The reversal of 23821989 is 98912832.

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 23821989 - 2⁹ = 23821477 is a prime.

It is a super-2 number, since 2×23821989² = 1134974319832242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 23821989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23821909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3970329 + ... + 3970334.

It is an arithmetic number, because the mean of its divisors is an integer number (7940664).

Almost surely, 2^23821989 is an apocalyptic number.

It is an amenable number.

23821989 is a deficient number, since it is larger than the sum of its proper divisors (7940667).

23821989 is an equidigital number, since it uses as much as digits as its factorization.

23821989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7940666.

The product of its digits is 62208, while the sum is 42.

The square root of 23821989 is about 4880.7774995384. Note that the first 3 decimals coincide. The cubic root of 23821989 is about 287.7349872137.

It can be divided in two parts, 2382 and 1989, that added together give a triangular number (4371 = T₉₃).

The spelling of 23821989 in words is "twenty-three million, eight hundred twenty-one thousand, nine hundred eighty-nine".