21524471 has 2 divisors, whose sum is σ = 21524472. Its totient is φ = 21524470.

The previous prime is 21524429. The next prime is 21524483. The reversal of 21524471 is 17442512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21524471 - 2¹⁴ = 21508087 is a prime.

It is a super-3 number, since 3×21524471³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21524471.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21524401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762235 + 10762236.

It is an arithmetic number, because the mean of its divisors is an integer number (10762236).

Almost surely, 2^21524471 is an apocalyptic number.

21524471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21524471 is an equidigital number, since it uses as much as digits as its factorization.

21524471 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 26.

The square root of 21524471 is about 4639.4472731135. The cubic root of 21524471 is about 278.1703448518.

Adding to 21524471 its reverse (17442512), we get a palindrome (38966983).

The spelling of 21524471 in words is "twenty-one million, five hundred twenty-four thousand, four hundred seventy-one".