21244040423 has 2 divisors, whose sum is σ = 21244040424. Its totient is φ = 21244040422.

The previous prime is 21244040401. The next prime is 21244040449. The reversal of 21244040423 is 32404044212.

It is a happy number.

It is an a-pointer prime, because the next prime (21244040449) can be obtained adding 21244040423 to its sum of digits (26).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21244040423 - 2²² = 21239846119 is a prime.

It is a super-3 number, since 3×21244040423³ (a number of 32 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21244040392 and 21244040401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21244040453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10622020211 + 10622020212.

It is an arithmetic number, because the mean of its divisors is an integer number (10622020212).

Almost surely, 2^21244040423 is an apocalyptic number.

21244040423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21244040423 is an equidigital number, since it uses as much as digits as its factorization.

21244040423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6144, while the sum is 26.

Adding to 21244040423 its reverse (32404044212), we get a palindrome (53648084635).

The spelling of 21244040423 in words is "twenty-one billion, two hundred forty-four million, forty thousand, four hundred twenty-three".