21530007 has 24 divisors (see below), whose sum is σ = 33256080. Its totient is φ = 13374720.

The previous prime is 21529997. The next prime is 21530017. The reversal of 21530007 is 70003512.

It is an interprime number because it is at equal distance from previous prime (21529997) and next prime (21530017).

It is not a de Polignac number, because 21530007 - 2⁸ = 21529751 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530017) 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 23 ways as a sum of consecutive naturals, for example, 16032 + ... + 17322.

It is an arithmetic number, because the mean of its divisors is an integer number (1385670).

Almost surely, 2^21530007 is an apocalyptic number.

21530007 is a deficient number, since it is larger than the sum of its proper divisors (11726073).

21530007 is a wasteful number, since it uses less digits than its factorization.

21530007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1423 (or 1420 counting only the distinct ones).

The product of its (nonzero) digits is 210, while the sum is 18.

The square root of 21530007 is about 4640.0438575513. The cubic root of 21530007 is about 278.1941908737.

Adding to 21530007 its reverse (70003512), we get a palindrome (91533519).

The spelling of 21530007 in words is "twenty-one million, five hundred thirty thousand, seven".