21249585 has 72 divisors (see below), whose sum is σ = 44815680. Its totient is φ = 9269568.

The previous prime is 21249583. The next prime is 21249587. The reversal of 21249585 is 58594212.

It is an interprime number because it is at equal distance from previous prime (21249583) and next prime (21249587).

It is not a de Polignac number, because 21249585 - 2¹ = 21249583 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21249583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 50506 + ... + 50924.

It is an arithmetic number, because the mean of its divisors is an integer number (622440).

Almost surely, 2^21249585 is an apocalyptic number.

It is an amenable number.

21249585 is an abundant number, since it is smaller than the sum of its proper divisors (23566095).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21249585 is a wasteful number, since it uses less digits than its factorization.

21249585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467 (or 457 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 21249585 is about 4609.7272153567. The cubic root of 21249585 is about 276.9811097215.

The spelling of 21249585 in words is "twenty-one million, two hundred forty-nine thousand, five hundred eighty-five".