21524423 has 2 divisors, whose sum is σ = 21524424. Its totient is φ = 21524422.

The previous prime is 21524401. The next prime is 21524429. The reversal of 21524423 is 32442512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21524423 - 2¹⁰ = 21523399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21524429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762211 + 10762212.

It is an arithmetic number, because the mean of its divisors is an integer number (10762212).

Almost surely, 2^21524423 is an apocalyptic number.

21524423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21524423 is an equidigital number, since it uses as much as digits as its factorization.

21524423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 23.

The square root of 21524423 is about 4639.4421000806. The cubic root of 21524423 is about 278.1701380765.

Adding to 21524423 its reverse (32442512), we get a palindrome (53966935).

The spelling of 21524423 in words is "twenty-one million, five hundred twenty-four thousand, four hundred twenty-three".