21443240023 has 4 divisors (see below), whose sum is σ = 21563034840. Its totient is φ = 21323445208.

The previous prime is 21443240017. The next prime is 21443240029. The reversal of 21443240023 is 32004234412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21443240017) and next prime (21443240029).

It is a cyclic number.

It is not a de Polignac number, because 21443240023 - 2⁵ = 21443239991 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21443240023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443240029) 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, 59897140 + ... + 59897497.

It is an arithmetic number, because the mean of its divisors is an integer number (5390758710).

Almost surely, 2^21443240023 is an apocalyptic number.

21443240023 is a deficient number, since it is larger than the sum of its proper divisors (119794817).

21443240023 is a wasteful number, since it uses less digits than its factorization.

21443240023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119794816.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21443240023 its reverse (32004234412), we get a palindrome (53447474435).

The spelling of 21443240023 in words is "twenty-one billion, four hundred forty-three million, two hundred forty thousand, twenty-three".