21893423 has 2 divisors, whose sum is σ = 21893424. Its totient is φ = 21893422.

The previous prime is 21893393. The next prime is 21893441. The reversal of 21893423 is 32439812.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21893423 - 2⁸ = 21893167 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21893423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21893483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10946711 + 10946712.

It is an arithmetic number, because the mean of its divisors is an integer number (10946712).

Almost surely, 2^21893423 is an apocalyptic number.

21893423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21893423 is an equidigital number, since it uses as much as digits as its factorization.

21893423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 32.

The square root of 21893423 is about 4679.0408205101. The cubic root of 21893423 is about 279.7507262759.

It can be divided in two parts, 2189 and 3423, that multiplied together give a palindrome (7492947).

The spelling of 21893423 in words is "twenty-one million, eight hundred ninety-three thousand, four hundred twenty-three".