21524513 has 2 divisors, whose sum is σ = 21524514. Its totient is φ = 21524512.

The previous prime is 21524501. The next prime is 21524539. The reversal of 21524513 is 31542512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19298449 + 2226064 = 4393^2 + 1492^2 .

It is a cyclic number.

It is not a de Polignac number, because 21524513 - 2²⁴ = 4747297 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21524593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762256 + 10762257.

It is an arithmetic number, because the mean of its divisors is an integer number (10762257).

Almost surely, 2^21524513 is an apocalyptic number.

It is an amenable number.

21524513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21524513 is an equidigital number, since it uses as much as digits as its factorization.

21524513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 23.

The square root of 21524513 is about 4639.4517995125. The cubic root of 21524513 is about 278.1705257799.

The spelling of 21524513 in words is "twenty-one million, five hundred twenty-four thousand, five hundred thirteen".